垂直磁记录介质的制备和超快自旋动力学研究
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摘要
人类社会步入信息化时代后,信息总量不断增大,传输速度越来越快。硬盘是信息存储的最佳介质,人们对其存储密度和信息处理速度不断提出更高的要求。垂直磁记录作为这两年工业界的新星受到了广泛的关注。为了真正实现每平方英寸1Tbit的存储密度,人们需要不断进行材料创新和开发新的记录方式来满足大众的需求。
基于磁光克尔效应的时间分辨泵浦—探测技术可以用来研究磁性材料自旋瞬态翻转的特性和磁性体系中磁化翻转的速度极限,对磁记录工业应用如热辅助磁记录有重要的意义。为了提高信噪比,磁记录介质必须是颗粒膜,而对其超快自旋动力学过程的研究还没有报道。
本论文就是在上述背景下展开研究的。本论文主要包含以下几个内容:
第一,我们研究了两种不同织构的种子层和热处理对CoCrPt垂直磁记录介质的影响,得到了性能较优的CoCrPt垂直磁记录介质。Cu和Cr两种种子层材料的运用较直接生长在玻璃上CoCrPt的矫顽力有很大的提高。而两类材料得到的CoCrPt介质的成核场和磁化翻转方式不同,以Cr为种子层的材料成核场为负,磁化翻转方式倾向于畴壁位移;以Cu为种子层的材料成核场为正,磁化翻转方式倾向于一致转动。我们分别从退火时间、生长温度和种子层厚度三个方面进行优化分析。
第二,我们研究了L1_0 FePt-CoCrPt垂直交换耦合体系。CoCrPt颗粒膜能有效地降低FePt垂直磁记录介质的写入场。当软磁层厚度小于一个临界值时,双层薄膜表现为刚性磁体行为。当软磁层厚度大于临界厚度时,双层膜表现出弹性磁体行为。弹性磁体的磁化翻转过程分为三个阶段,首先是软磁的可逆磁化翻转,形成N(?)el壁,然后N(?)el壁被挤压推向硬磁,最后硬磁形成多畴以Bloch畴壁位移的方式进行反磁化以降低系统畴壁能。
第三,我们研究了L1_0 FePt颗粒膜的自旋动力学和瞬态磁软化过程。当泵浦光激发薄膜的时候,样品发生了磁软化过程。反射率、克尔角、矫顽力,矩形度,磁化翻转方式都经历了快速变化随后缓慢恢复的过程。三个样品的热磁响应按强弱顺序依次为:FePt-MgO颗粒膜＞FePt单层＞FePt-Ag颗粒膜。FePt-Ag颗粒膜比FePt单层的热退磁效果弱主要是因为Ag提供了大量的自由电子分走了入射的pump光能量,所以FePt吸收到的能量就小。而FePt-MgO颗粒膜中由于存在表面等离子共振,电子的温度更高,热磁响应就更大,磁软化的效果就更佳。
With the development of information age,the volume of information is consistently increasing very fast,and the transmission speed is also accelerating very fast.Hard disk recording is the best storage medium,so people are keeping asking for higher areal density and faster information processing speed.Perpendicular magnetic recording has been a super star in the hard disk industry for the past two years,and it receives widespread concern.In order to truly realize 1Tbit per square inch storage density,it requires constant innovation and development of new materials to meet the needs of the public.
Magneto-optical Kerr effect with time-resolved pump-probe technique can be used to study the transient reversal of the magnetic spin and to explore the limit of magnetization reversal speed in magnetic systems.It has great impact on the magnetic recording industrial such as heat-assisted magnetic recording(HAMR).In order to improve the signal to noise ratio,magnetic recording media must be of granular configuration.However,ultra-fast spin dynamics research on magnetic granular film has not yet been reported.
This research work was carried out under the above background.The dissertation mainly includes the following contents.
Firstly,we carried research on effect of seed layer texture and heat treatment on CoCrPt perpendicular magnetic recording media.We got optimized parameter of making better CoCrPt media.Both Cu and Cr seed layer materials are observed to greatly improve the coercivity of CoCrPt media,compared with samples grown on bare glass.These two types of materials brings to different nucleation field of the CoCrPt media.Nucleation field of sample with Cr seed layer is negative,which is due to the domain wall displacement dominated magnetization reversal.Nucleation field of sample with Cu seed layer is positive,which is due to the collective rotation dominated magnetization reversal.We finally optimized the sample through three aspects:annealing time,growth temperature and seed layer thickness.
Secondly,we studied the L1_0 FePt-CoCrPt perpendicular exchange coupled system.CoCrPt granular soft layer is very effective in reducing the writing field of FePt hard layer.When the thickness of soft-magnetic layer is smaller than a critical value,the bilayer will act as a rigid magnet.When the thickness of soft layer becomes larger,the bilayer will act as an exchange spring media.For exchange spring media, the magnetization reversal process is divided into three stages.It begins with a reversible magnetization reversal in the soft layer and forms a N(?)el domain wall. Then,the domain wall is squeezed to the hard layer.Finally,multi-domain is formed in the hard layer to reduce the total energy of the system.
Thirdly,we studied the spin dynamics and transient magnetic softening in L1_0 FePt granular films.After the pump excitation,the reflectivity,Kerr angle,coercivity, rectangular degree and the magnetization reversal mode all undergo rapid change followed by the subsequent slow recovery.The thermal response strength of three samples goes like:FePt-MgO granular films＞FePt single layer＞FePt-Ag granular films.The thermal demagnetization in FePt-Ag granular films is smaller than FePt single layer.It is mainly due to allocation of incident pump energy by the free electrons in Ag,and the energy absorbed by FePt becomes smaller.What is more important is that FePt-MgO granular films have greater magnetic thermal response.It is due to the existence of surface plasmon resonance which brings to higher electron temperature,and consequently better magnet softening effect.
基于磁光克尔效应的时间分辨泵浦—探测技术可以用来研究磁性材料自旋瞬态翻转的特性和磁性体系中磁化翻转的速度极限,对磁记录工业应用如热辅助磁记录有重要的意义。为了提高信噪比,磁记录介质必须是颗粒膜,而对其超快自旋动力学过程的研究还没有报道。
本论文就是在上述背景下展开研究的。本论文主要包含以下几个内容:
第一,我们研究了两种不同织构的种子层和热处理对CoCrPt垂直磁记录介质的影响,得到了性能较优的CoCrPt垂直磁记录介质。Cu和Cr两种种子层材料的运用较直接生长在玻璃上CoCrPt的矫顽力有很大的提高。而两类材料得到的CoCrPt介质的成核场和磁化翻转方式不同,以Cr为种子层的材料成核场为负,磁化翻转方式倾向于畴壁位移;以Cu为种子层的材料成核场为正,磁化翻转方式倾向于一致转动。我们分别从退火时间、生长温度和种子层厚度三个方面进行优化分析。
第二,我们研究了L1_0 FePt-CoCrPt垂直交换耦合体系。CoCrPt颗粒膜能有效地降低FePt垂直磁记录介质的写入场。当软磁层厚度小于一个临界值时,双层薄膜表现为刚性磁体行为。当软磁层厚度大于临界厚度时,双层膜表现出弹性磁体行为。弹性磁体的磁化翻转过程分为三个阶段,首先是软磁的可逆磁化翻转,形成N(?)el壁,然后N(?)el壁被挤压推向硬磁,最后硬磁形成多畴以Bloch畴壁位移的方式进行反磁化以降低系统畴壁能。
第三,我们研究了L1_0 FePt颗粒膜的自旋动力学和瞬态磁软化过程。当泵浦光激发薄膜的时候,样品发生了磁软化过程。反射率、克尔角、矫顽力,矩形度,磁化翻转方式都经历了快速变化随后缓慢恢复的过程。三个样品的热磁响应按强弱顺序依次为:FePt-MgO颗粒膜＞FePt单层＞FePt-Ag颗粒膜。FePt-Ag颗粒膜比FePt单层的热退磁效果弱主要是因为Ag提供了大量的自由电子分走了入射的pump光能量,所以FePt吸收到的能量就小。而FePt-MgO颗粒膜中由于存在表面等离子共振,电子的温度更高,热磁响应就更大,磁软化的效果就更佳。
With the development of information age,the volume of information is consistently increasing very fast,and the transmission speed is also accelerating very fast.Hard disk recording is the best storage medium,so people are keeping asking for higher areal density and faster information processing speed.Perpendicular magnetic recording has been a super star in the hard disk industry for the past two years,and it receives widespread concern.In order to truly realize 1Tbit per square inch storage density,it requires constant innovation and development of new materials to meet the needs of the public.
Magneto-optical Kerr effect with time-resolved pump-probe technique can be used to study the transient reversal of the magnetic spin and to explore the limit of magnetization reversal speed in magnetic systems.It has great impact on the magnetic recording industrial such as heat-assisted magnetic recording(HAMR).In order to improve the signal to noise ratio,magnetic recording media must be of granular configuration.However,ultra-fast spin dynamics research on magnetic granular film has not yet been reported.
This research work was carried out under the above background.The dissertation mainly includes the following contents.
Firstly,we carried research on effect of seed layer texture and heat treatment on CoCrPt perpendicular magnetic recording media.We got optimized parameter of making better CoCrPt media.Both Cu and Cr seed layer materials are observed to greatly improve the coercivity of CoCrPt media,compared with samples grown on bare glass.These two types of materials brings to different nucleation field of the CoCrPt media.Nucleation field of sample with Cr seed layer is negative,which is due to the domain wall displacement dominated magnetization reversal.Nucleation field of sample with Cu seed layer is positive,which is due to the collective rotation dominated magnetization reversal.We finally optimized the sample through three aspects:annealing time,growth temperature and seed layer thickness.
Secondly,we studied the L1_0 FePt-CoCrPt perpendicular exchange coupled system.CoCrPt granular soft layer is very effective in reducing the writing field of FePt hard layer.When the thickness of soft-magnetic layer is smaller than a critical value,the bilayer will act as a rigid magnet.When the thickness of soft layer becomes larger,the bilayer will act as an exchange spring media.For exchange spring media, the magnetization reversal process is divided into three stages.It begins with a reversible magnetization reversal in the soft layer and forms a N(?)el domain wall. Then,the domain wall is squeezed to the hard layer.Finally,multi-domain is formed in the hard layer to reduce the total energy of the system.
Thirdly,we studied the spin dynamics and transient magnetic softening in L1_0 FePt granular films.After the pump excitation,the reflectivity,Kerr angle,coercivity, rectangular degree and the magnetization reversal mode all undergo rapid change followed by the subsequent slow recovery.The thermal response strength of three samples goes like:FePt-MgO granular films＞FePt single layer＞FePt-Ag granular films.The thermal demagnetization in FePt-Ag granular films is smaller than FePt single layer.It is mainly due to allocation of incident pump energy by the free electrons in Ag,and the energy absorbed by FePt becomes smaller.What is more important is that FePt-MgO granular films have greater magnetic thermal response.It is due to the existence of surface plasmon resonance which brings to higher electron temperature,and consequently better magnet softening effect.
引文
[1]http://www.seagate.com
[2]查超麟.L1_(0)FePt基磁记录介质材料的研究[D],上海:复旦大学,2006.
[3]E.Beaurepaire,J.C.Merle,A.Daunois,and J.Y.Bigot.Ultrafast spin dynamics in ferromagnetic nickel[J].Phys.Rev.Lett.,1996,76:4250-4253.
[4]J.M.Kikkawa and D.D.Awschalom.All-optical magnetic resonance in semiconductors[J].Science,2000,287:473-476.
[5]J.A.Gupta,R.Knobel,N.Samarth,and D.D.Awschalom.Ultrafast manipulation of electron spin coherence[J].Science,2001,292:2458-2461.
[6]G.Ju,A.Vertikov,A.V.Nurmikko,C.Canady,G.Xiao,R.F.C.Farrow,and A.Cebollada.Ultrafast nonequilibrium spin dynamics in a ferromagnetic thin film[J]. Phys.Rev.B,1998,57:R700-R703.
[7]T.Kampfrath,R.G.Ulbrich,F.Leuenberger,M.Munzenberg,B.Sass and W.Felsch.Ultrafast magneto-optical response of iron thin films[J].Phys.Rev.B,2002,65:104429-1-6.
[8]P.Gr(u|¨)nberg,R.Schreiber,Y.Pang,M.B.Brodsky and H.Sowers.Layered Magnetic Structures:Evidence for Antiferromagnetic Coupling of Fe Layers across Cr Interlayers[J].Phys.Rev.Lett.1986,57:2442-2445.
[9]Bin Lu.Data Storage Overview[R].上海:复旦大学光科学与工程系,2004.
[10]P.J.Grundy,Thin film magnetic recording media[J].J.Phys.D:Appl.Phys.,1998,31:2975-2990.
[11]D.A.Thompson,J.S.Best,The future of magnetic data storage technology[J],IBM J.RES.DEVELOP.,2000,44(3):311-322.
[12]Y.Sonobe,H.Muraoka,K.Miura,and Y.Nakamura,et al.,Coupled granular/continuous perpendicular recording media with soft magnetic underlayer[J].J.Appl.Phys.,2002,91:8055-8057.
[13]H.Nakagawa,H.Nakagawa,H.Nemoto,Y.Honda,T.Ichihara,K.Tanahashi,and Y.Hosoe.Thermal stability and recording characteristics of TbCo/CoCrPt-hybrid media for perpendicular recording[J].J.Appl.Phys.,2002,91:8016-8018.
[14]Jian-Ping Wang,Weikang Shen,Jianmin Bai.Exchange coupled composite media for perpendicular magnetic recording[J].IEEE Trans.Magn.,2005,41:3181-3186.
[15]Jian-Ping Wang,W.K.Shen,J.M.Bai,et al.Composite media(dynamic tilted media)for magnetic recording[J],Appl.Phys.Lett.2005,86:142504:1-3.
[16]Mark H.Kryder,Future Materials Research in Data Storage[R]USA.NSF Workshop(2006)
[17]Shouheng Sun,C.B.Murray,Dieter Weller,Liesl Folks,Andreas Moser,Science 2000,Vol.287.no.5460,pp.1989-1992
[18]J.Y.Bigot.Femtosecond magneto-optical processes in metals[J].C.R.Acad.Sci.,2001,2:1483-1504.
[19]Bloch F.Nuclear Induction[J].Phys.Rev.1946,70:460-474.
[20]L.Landau,and L.Lifshitz.On the theory of the dispersion of magnetic permeability in ferromagnetic bodies[J].Phys.Z.Sowjetunion,1935,8:153.
[21]T.L.Gilbert.A Lagrangian Formulation of the Gyromagnetic Equation of the Magnetization Field[J].Phys.Rev.,1935,100:1243.
[22] J. Ferr(?), V. Grolier, P. Meyer, S. Lemerle, A. Maziewski, E. Stefanowicz, S. V. Tarasenko, V. V. Tarasenko, M. Kisielewski, and D. Renard. Magnetization-reversal processes in an ultrathin Co/Au film [J]. Phys. Rev. B, 1997, 55: 15092-15102.
[23] M. B. Agranat, S. I. Ashikov, A. B. Granovskii, and G. I. Rukman. Interaction of picosecond laser pulses with the electron, spin and phonon subsystem of nickel [J]. Sov. Phys. JETP, 1984, 59: 804-806.
[24] A. Vaterlaus, T. Beutler, and F. Meier. Spin-lattice relaxation time of ferromagnetic gadolinium determined with time-resolved spin-polarized photoemission [J]. Phys. Rev. Lett., 1991, 67: 3314-3317 .
[25] A. Vaterlaus, T. Beutler, D. Guarisco, M. Lutz, and F. Meier. Spin-lattice relaxation in ferromagnets studied by time-resolved spin-polarized photoemission [J]. Phys. Rev. B, 1992,46: 5280-5286.
[26] J. Hohlfeld, E. Matthias, R. Knorren, and K. H. Bennemann. Nonequilibrium magnetization dynamics of nickel [J]. Phys. Rev. Lett. 1997, 78: 4861-4864.
[27] J. Gudde, U. Conrad, V. Jahnke, J. Hohlfeld, and E. Matthias. Magnetization dynamics of Ni and Co .lms on Cu(001) and of bulk nickel surfaces [J]. Phys. Rev. B, 1999,59:R6608-R6611.
[28] J. Hohlfeld, J. Gudde, U. Conrad, O. Duhr, G Korn, and E. Matthias. Ultrafast magnetization dynamics of nickel [J]. Appl. Phys. B, 1999, 68: 505-510.
[29] A. Scholl, L. Baumgarten, R. Jacquemin, and W. Eberhardt. Ultrafast spin dynamics of ferromagnetic thin films observed by femtosecond spin-resolved two photon photemission [J]. Phys. Rev. Lett., 1997, 79: 5146-5149.
[30] U. Conrad, J. Gudde, V. Jahnke, and E. Matthias. Ultrafast magnetization and electron dynamics of thin Ni and Co films on Cu(001) observed by time-resolved SHG [J]. Appl. Phys. B, 1999, 68: 511-517.
[31] J. Hohlfeld. Utrafast electron, lattice and spin dynamics in metals: Investigated by linear and nonlinear optical techniques [D]. Ph.D. Thesis, Berlin: Freie University,, 1998.
[32] M. Aeschlimann, M. Bauer, S. Pawlik, W. Weber, R. Burgermeister, D. Oberli, and H.C. Siegmann. Ultrafast spin-dependent electron dynamics in fcc Co [J]. Phys. Rev. Lett., 1997, 79: 5158-5161.
[33] R. Knorren, K. H. Bennemann, R. Burgermeister, and M. Aeschlimann. Dynamics of excited electrons in copper and ferromagnetic transition metals: Theory and experiment [J]. Phys. Rev. B, 2000, 61: 9427-9440.
[34] E. Beaurepaire, M. Maret, V. Halte, J. C. Merle, A. Daunois, and J. Y. Bigot. Spin dynamics in CoPt3 alloy films: A magnetic phase transition in the femtosecond time scale [J]. Phys. Rev. B, 1998, 58:12134-12137.
[35] J. Hohlfeld, T. Gerrits, M. Bilderbeek, T. Rasing, H. Awano, and N. Ohta. Fast magnetization reversal of GdFeCo induced by femtosecond laser pulses [J]. Phys. Rev. B, 2001, 65: 012413:1-4.
[36] G. Ju, A. Vertikov, A.V. Nurmikko, C. Canady, G. Xiao, R. F. C. Farrow, and A. Cebollada. Ultrafast nonequilibrium spin dynamics in a ferromagnetic thin film, [J] Phys. Rev. B, 1998, 57: R700-R703.
[37] T. Kise, T. Ogasawara, M. Ashida, Y. Tomioka, Y. Tokura, and M. Kuwata-Gonokami. Ultrafast spin dynamics and critical behavior in half-metallic ferromagnet: Sr2FeMoO6 [J]. Phys. Rev. Lett., 2000, 85: 1986-1989.
[38] B. Koopmans, M. van Kampen, J. T. Kohlhepp, and W. J. M. de Jonge. Ultrafast magneto-optics in nickel; magnetism or optics? [J]. Phys. Rev. Lett., 2000, 85: 844-847.
[39] B. Koopmans, M. van Kampen, J. T. Kohlhepp, and W. J. M. de Jonge. Experimental access to femtosecond spin dynamics [J]. J. Phys.: Condens. Matt., 2002, 14: 1-14.
[40] B. Koopmans, M. van Kampen, J. T. Kohlhepp, and W. J. M. de Jonge. Femtosecond spin dynamics of epitaxial Cu(111)/Ni/Cu wedges [J]. J. Appl. Phys., 2000, 87: 5070-5072.
[41] B. Hillebrands, and K. Ounadjela (Eds.). Spin Dynamics in Confined Magnetic Structures II [M]. Topics Appl. Phys. 2003, 87: 253-320.
[42] B. Sinkovic, L. H. Tjeng, N. B. Brookes, J. B. Goedkoop, R. Hesper, E. Pellegrin, F. M. F. de Groot, S. Altieri, S. L. Hulbert, E. Shekel, and G A. Sawatzky. Local Electronic and Magnetic Structure of Ni below and above T_c: A spin-resolved circularly polarized resonant photoemission study [J]. Phys. Rev. Lett., 1997, 79: 3510-3513.
[43] T. J. Kreutz, T. Greber, P. Aebi, and J. Osterwalder. Temperature-dependent electronic structure of nickel metal [J]. Phys. Rev. B, 1998, 58: 1300-1317.
[44] M. Farle. Ferromagnetic resonance of ultrathin metallic layers [J]. Prog. Rep. Phys., 1998, 61:755-826.
[45] G. Ju, A.V. Nurmikko, R. F. C. Farrow, R. F. Marks, M. J. Carey, and B. A. Gurney. Coherent magnetization rotation by optical modulation in ferromagnetic /antiferromagnetic exchange-coupled bilayers[J].Phys.Rev.B,2000,62:1171-1177.
[46]G Ju,A.V Nurmikko,R.F.C.Farrow,R.F.Marks,M.J.Carey,and B.A.Gumey.Ultrafast optical modulation of an exchange biased ferromagnetic /antiferromagnetic bilayer[J].Phys.Rev.B,1998,58:R11857-R11860.
[1]张以忱,真空工艺与实验技术[M].北京:冶金工业出版社,2006.
[2]张树林,真空技术物理基础[M].沈阳:东北工学院出版社,1988.
[3]杨乃恒,真空获得设备.第二版[M].北京:冶金工业出版社,2001.
[4]彭勇,硕士毕业论文[D].兰州:兰州大学,2001.
[5]赵宝升,真空技术[M].北京:科学出版社,1998.
[6]郑伟涛,薄膜材料与薄膜技术[M].北京:化学工业出版社,2004.
[7]杨邦朝,王文生.薄膜物理与技术[M].北京:电子科技大学出版社,1994.
[8]吴自勤,王兵.薄膜生长[M].北京:科学出版社,2001.
[9]唐伟忠,薄腊材料制备原理、技术及应用(第2版)[M].北京:冶金工业出版社,2003.
[10]田民波,刘德令.薄膜科学与技术手册[M].北京:机械工业出版社,1991.
[11]王力衡,黄运添,郑海涛.薄膜技术[M].北京:清华大学出版社,1991.
[12]S.Jeon.Structure and magnetic properties of polycrystalline FePt and CoPt thin films for high density recording media[D],USA,PA:Carnegie Mellon University,2002.
[13]Warren B.E.,X-ray diffraction[M]Dover,New York,1990:208
[14]黄孝瑛,透射电子显微学[M].上海:上海科学技术出版社,1987.
[15]佚名.大唐网资料库[EB/OL].http://info.datang.net/ZF/ZF0056.htm,2004-1-1.
[16]X.M.Ding,X.Yang,and W.Xun,Surface physics and surface analysis [M].Shanghai,Fudan University,2007.
[17]周文生.磁性测量原理[M]北京:电子工业出版社,1988.
[18]Berger L,Bergmann G,Chien C L,et al,The Hall Effect and Its Applications[M].New York:Plenum,1979:55.
[19]Karplus R,Luttinger J M,Hall Effect in Ferromagnetics[J],Phys.Rev.,1954,95(5):1154-1160.
[20]Smit J,The spontaneous hall effect in ferromagnetics Ⅱ.Physica (Utrecht)[M],1958,24:39-51.
[21]R.M.Osgood,S.D.Bader,B.M.Clemens,R.L.White and H.Matsuyama.Second-order magneto-optic effects in anisotropic thin films[J].J.Magn.Man.Mater.,1998,182:297-323.
[22]M.Thomas.Faraday Diary[M].Londan,ibid,1845:7437-7444.
[23]白春礼,田芳,罗克.扫描力显微术[M].北京:科学出版社,2000.
[24]G.L.Eesley.Observation of Nonequilibrium Electron Heating in Copper[J].Phys.Rev.Lett.,1983,51:2140-2143.
[25]J.Hohlfeld,J.Gudde,U.Conrad,O.Duhr,G.Korn and E.Matthias.Ultrafast magnetization dynamics of nickel[J].Applied Physics B Lasers and Optics,1999,68,3:505-510.
[1]J.Zhou,R.Skomski,and X.Z.Li et al.Permanent-magnet properties of thermally processed FePt and FePt-Fe multilayer films[J],IEEE Trans.Magn.,2002,38:2802-2804.
[1]S.Iwasaki,Y.Nakamura,An analysis for the magnetization mode for high density magnetic recording[J]IEEE Trans.Magn.Mag.1977,13:1272-1277.
[2]S.Iwasaki,Y.Nakamura,K.Ouchi,Perpendicular magnetic recording with a composite anisotropy film[J]IEEE Trans.Magn.Mag.1979,15:1456-1458.
[3]Z.Xu,H.N.Hu,S.M.Zhou,S.L.Ren,X.X.Zhang.Combined effects of heat treatment and seed layer materials on magnetic properties of CoCrPt perpendicular media[J]Thin Solid Films 2008,516:2071-2077.
[4]G.M.Chow,C.J.Sun,E.W.Soo,J.P.Wang,H.H.Lee,D.Y.Noh,T.S.Cho,J.H.Je,Y.K.Hwu,Structural study of CoCrPt films by anomalous x-ray scattering and extended x-ray absorption fine structure[J]Appl.Phys.Lett.2002,80:1607-1609.
[5]Pawel Glijer,John M.Sivertsen,and Jack H.Judy.Effects of platinum content and substrate bias on the structure and magnetic properties of CoCrPt/Cr thin films[J]J.Appl.Phys.1993,73:5563-5565.
[6]A.Sato,S.Nakagawa,M.Naoe,Co-Cr-Ta Perpendicular Magnetic Recording Media Using Pt Seed Layer[J]IEEE Trans.Magn.2000,36:2387-2389.
[7]S.Saito,N.Itagaki,M.Takahashi,Improvement of perpendicular magnetic properties by postannealing for M'-CoCrPt-M stacked media(M,M'=Ti,Ta,Ru,Pt,CrMn,MnSi)[J]IEEE Trans.Magn.2004,40:2467-2469.
[8]P.W.Jiang,S.Y.Hong,J.Y.Kim,Role of Ag seed layer for CoCrPt/Ti perpendicular recording media[J]J.Appl.Phys.2003,93:7741-7743.
[9]A.G.Roy,D.E.Laughlin,Effect of seed layers in improving the crystallographic texture of CoCrPt perpendicular recording media[J]J.Appl.Phys.2002,91:8076-8078.
[10]Y.J.Kim,W.H.Park,S.H.Kong,S.Nakagawa,K.H.Kim,Improvement of c-axis preferred orientation of CoCr-based thin film with amorphous Si underlayer[J]Surf.Coat.Technol.2003,532:169-170.
[11]M.H.Hu,S.Noda,H.Komiyama,Amorphous-to-crystalline transition during the early stages of thin film growth of Cr on SiO_2[J]J.Appl.Phys.2003,93:9336-9344.
[12]高铁仁 垂直磁记录介质的制备及物性研究[D],上海:复旦大学,2006.
[1]Zhen Xu,Shiming Zhou,JJ Ge,Jun Du,Li Sun Magnetization reversal mechanism of perpendicularly exchange-coupled composite L10-FePt/CoCrPt bilayers[J].accepted by J.Applied Physics,2009.
[2]R.H.Victora and X.Shen,Composite media for perpendicular recording[J].IEEE Trans.Magn.2005,41:537-542.
[3]D.Suess,T.Schrefl,R.Dittrich,M.Kirschner,F.Dorfbauer,G.Hrkac,and J.Fidler,Exchange spring recording media for areal densities up to 10 Tbit/in~2[J].J.Magn.Magn.Mater.2005,290:551-554.
[4] A. Y. Dobin and H. J. Richter, Domain wall assisted magnetic recording [J]. Appl. Phys. Lett. 2006, 89: 062512:1-3.
[5] M. Ghidini, G. Asti, R. Pellicelli, C. Pemechele, and M. Solzi, Hard-soft composite magnets [J]. J. Magn. Magn. Mater. 2007,316: 159-165.
[6] H. Kronmiiller and D. Goll, Pinning of domain walls in composite particles [J]. Physica B 2008,403: 237-241.
[7] D. Suess, Micromagnetics of exchange spring media: Optimization and limits [J]. J. Magn. Magn. Mater. 2007, 308: 183-197.
[8] B. Livshitz, A. Inomata, H. N. Bertram, and V. Lomakin, Precessional reversal in exchange-coupled composite magnetic elements [J]. Appl. Phys. Lett. 2007, 91: 182502:1-3.
[9] D. Goll, S. Macke, and H. N. Bertram, Thermal reversal of exchange spring composite media in magnetic fields [J]. Appl. Phys. Lett. 2007, 90: 172506:1-3.
[10] E. E. Fullerton, J. S. Jiang, M. Grimsditch, C. H. Sowers, and S. D. Bader, Exchange-spring behavior in epitaxial hard/soft magnetic bilayers [J]. Phys. Rev. B 1998, 58: 12193-12200.
[11] J. E. Davies, O. Hellwig, E. E. Fullerton, J. S. Jiang, S. D. Bader, G T. Zimanyi, and K. Liu, Anisotropy dependence of irreversible switching in Fe/SmCo and FeNi/FePt exchange spring magnet films [J]. Appl. Phys. Lett. 2005, 86: 262503:1-3.
[12] A. J. Zambano, H. Oguchi, I. Takeuchi, Y. Choi, J. S. Jiang, J. P. Liu, S. E. Lofland, D. Josell, and L. A. Bendersky, Dependence of exchange coupling interaction on micromagnetic constants in hard/soft magnetic bilayer systems [J]. Phys. Rev. B 2007, 75: 144429:1-7.
[13] Y. Choi, J. S. Jiang, J. E. Pearson, S. D. Bader, J. J. Kavich, J. W. Freeland, and J. P. Liu, Controlled interface profile in Sm-Co/Fe exchange-spring magnets [J]. Appl. Phys. Lett. 2007, 91: 072509:1-3.
[14] J. P. Wang, W. Shen, and S. Y. Hong, Fabrication and Characterization of Exchange Coupled Composite Media [J]. IEEE Trans. Magn. 2007, 43: 682-686.
[15] D. Goll, A. Breitling, and S. Macke, Magnetic Properties of Exchange-Coupled L1_0-FePt/Fe Composite Elements [J]. IEEE Trans. Magn. 2008, 44: 3472-3475.
[16] D. Goll, A. Breitling, L. Gu, P. A. van Aken, and W. Sigle Experimental realization of graded L1_0-FePt/Fe composite media with perpendicular magnetization [J]. J. Appl. Phys. 2008,104: 083903:1-4.
[17] F. Casoli, F. Albertini, S. Fabbrici, C. Bocchi, L. Nasi, R. Ciprian, and L.Pareti, Exchange-coupled FePt/Fe bilayers with perpendicular magnetization [J]. IEEE Trans. Magn. 2005,41: 3877-38779.
[18] D. Goll and A. Breitling, Coercivity of ledge-type L1_0-FePt/Fe nanocomposites with perpendicular magnetization [J]. Appl. Phys. Lett. 2009, 94: 052502:1-3.
[19] J. F. Hu, J. S. Chen, Y. F. Ding, B. C. Lim, W. L. Phyoe, and B. Liu Exchange coupling assisted FePtC perpendicular recording media [J]. Appl. Phys. Lett. 2008, 93: 072504:1-3.
[20] Hao Zeng, Jing Li, J. P. Liu, Zhong L. Wang and Shouheng Sun, Exchange-coupled nanocomposites magnets by nanoparticle self-assembly [J]. Nature 2002,420: 395-398.
[21] Yanglong Hou, Zhichuan Xu, Sheng Peng, Chuanbing Rong, J. Ping Liu, and Shouheng Su, A facile synthesis of SmCo_5 magnets from Core/Shell Co/Sm_2O_3 nanoparticles [J]. Advanced Materials, 2007,19: 3349-3352.
[22] Yanglong Hou, Shouheng Sun, Chuanbing Rong, and J. Ping Liu SmCo_5/Fe nanocomposites synthesized from reductive annealing of oxide nanoparticles [J]. Appl. Phys. Lett., 2007, 91: 153117:1-3.
[23] Chuan-bing Rong, Vikas Nandwana, Narayan Poudyal, J.P. Liu, Tetsuji Saito, Yaqiao Wu, and Matthew J. Kramer Bulk FePt/Fe3_Pt nanocomposite magnets prepared by spark plasma sintering [J]. J. Applied Physics, 2007,101: 09K515:1-3.
[24] R. Pellicelli, C. Pernechele, M. Solzi, M. Ghidini, F. Casoli, and F. Albertini, Modeling and characterization of irreversible switching and viscosity phenomena in perpendicular exchange-spring Fe-FePt bilayers [J]. Phys. Rev. B 1998, 78: 184434:1-10.
[25] R. Wood, Y. Sonobe, Z. Jin, and B. Wilson, Perpendicular recording: the promise and the problems [J]. J. Magn. Magn. Mater. 2001,235: 1-9.
[26] D. Weller, A. Moser, L. Folks, M. E. Best, W. Lee, M. F. Toney, M. Schwickert, J.-U. Thiele, and M. F. Doerner, High Ku materials approach to 100 Gbits/in~2 [J]. IEEE Trans. Magn. 2000, 36: 10-15.
[27] G. Asti, M. Ghidini, R. Pellicelli, C. Pernechele, M. Solzi, F. Albertini, F. Casoli, S. Fabbrici, and L. Pareti. Magnetic phase diagram and demagnetization processes in perpendicular exchange-spring multilayers [J]. Phys. Rev. B 2006, 73: 094406.
[28] J. P. Wang, W. K. Shen, J. M. Bai, R. H. Victora, J. H. Judy, and W. L. Song. Composite media(dynamic tilted media) for magnetic recording [J]. Appl. Phys. Lett. 2005, 86: 142504.
[29] D. Golla and S. Macke, Thermal stability of ledge-type L10-FePt/Fe exchange-spring nanocomposites for ultrahigh recording densities, [J]. Appl. Phys. Lett. 2008, 93: 152512.
[30] Vitaliy Lomakin, Richard Choi, Boris Livshitz, Shaojing Li, Akihiro Inomata, and H. Neal Bertram, Dual-layer patterned media "ledge" design for ultrahigh density magnetic recording. [J]. Appl. Phys. Lett. 2008, 92: 022502.
[31] C. Byun, J. M. Sivertsen, and J. H. Judy. A study on magnetization reversal mechanisms of CoCr films, [J]. IEEE Trans. Magn. 1986,22: 1155-1157.
[32] D. Givord, P. Tenaud, and T. Viadieu, Angular dependence of coercivity in sintered magnets [J]. J. Magn. Magn. Mater. 1988, 72: 247-252.
[33] X. M. Cheng, S. Urazhdin, O. Tchernyshyov, C. L. Chien, V. I. Nikitenko, A. J. Shapiro, and R. D. Shull, Antisymmetric Magnetoresistance in Magnetic Multilayers with Perpendicular Anisotropy [J]. Phys. Rev. Lett. 2005, 94: 017203.
[34] F. Garcia-Sanchez, O. Chubykalo-Fesenko, O. Mryasov,P. Asselin, and R. W. Chantrell, Switching and thermal stability properties of bilayer thin films: Single versus multigrain cases [J]. J. Appl. Phys. 2008,103: 07F505.
[1]Massalski T.Binary alloy phase diagrams[M].2nd Edition.Ohio:Metals Park,1990.
[2]Y.K.Takahashi,T.Koyama,M.Ohnuma,T.Ohkubo,and K.Hono,Size dependence of ordering in FePt nanoparticles[J]J.Appl.Phys.2004,95:2690-2696.
[3]Platt,CL;Wierman,KW;Svedberg,EB,et al.L10 ordering and microstructure of FePt thin films with Cu,Ag,and Au additive[J].J Appl Phys,2002,92:6104-6109.
[4]Yan M L,Sabirianov R F,Xu Y F,et al,L10 ordered FePt:C composite films with[001]texture[J].IEEE Trans Magn,2004,40:2 47022.
[5]Luo C P,Liou S H,Gao L,et al,Nanostructured FePt:B203 thin films with perpendicular magnetic anisot ropy[J].Appl Phys Lett,2000,77:2225-2227.
[6]Kim H J,Lee S R.Texture development and magnetic properties of sputter deposited FePt MgO nanocomposite films[J].J Appl Phys,2005,97:10H304.
[7] Sakurai R, Yamamoto Y, Chen C , et al , Structure and magnetic behavior of reactive sputter deposited nanocomposite FePtTiN films [J] . Thin Solid Films , 2004,459:208-211.
[8] Bai J , Yang Z , Wei F , et al. Nanocomposite FePtA12O3 films for high2density magnetic recording [J ] J Magn Magn Mater, 2003 ,257: 132-137
[9] Daniil M , Farber P A , Okumura H , et al. FePt/ BN granular films for high density recording media [J] J Magn Magn Mater, 2002 ,246: 297-302.
[10] H.R.Hulme, [C] Proc.R.Soc.London, Ser.A 1932,135: 237.
[11] C.Kittel, Optical rotation by ferromagnetic substances [J] Phys.Rev. 1951, 83: 208-210.
[12] P.N.Argyres, Theory of the Faraday and Kerr Effects in Ferromagnetics [J] Phys.Rev. 1955, 97: 334-345.
[13] G.Y. Guo, H. Ebert. On the origins of the enhanced magneto-optical Kerr effect in ultrathin Fe and Co multilayers[J],Journal of Magnetism and Magnetic Materials 1996,156: 173-174.
[14] L. Uba, S. Uba, V. N. Antonov, A. N. Yaresko, and R. Gontarz. Microscopic origin of the magneto-optical properties of CoPt alloys [J].Phys. Rev. B 2001, 64: 125105.
[15] Till, Burkert, Olle, Eriksson, Sergei, I. Simak, Andrei, V. Ruban, Biplab, Sanyal, Lars, Nordstrom, and John, M. Wills, Magnetic anisotropy of L1_0 FePt and Fe_(1-x)Mn_xPt [J] Physical Review B 2005, 71: 134411.
[16] Brown, G., Kraczek, B., Janotti, A., Schulthess, T. C., Stocks, G. M., and Johnson, D. D., Competition between ferromagnetism and antiferromagnetism in FePt [J] Physical Review B 2003, 68: 052405.
[17] Staunton, J. B., Ostanin, S., Razee, S. S. A., Gyorffy, B. L., Szunyogh, L., Ginatempo, B., and Ezio, Bruno, Temperature Dependent Magnetic Anisotropy in Metallic Magnets from an Ab Initio Electronic Structure Theory: L1_0-Ordered FePt [J] Physical Review Letters 2004, 93: 257204.
[18] Kitakami, Osamu, Okamoto, Satoshi, Kikuchi, Nobuaki, and Shimada, Yutaka, Energy Barrier Enhanced by Higher Order Magnetic Anisotropy Terms [J] Jpn J Appl Phys 2003, 42: L455 (part2).
[19] E. Beaurepaire, J. C. Merle, A. Daunois, and J. Y. Bigot. Ultrafast spin dynamics in ferromagnetic nickel [J]. Phys. Rev. Lett., 1996, 76: 4250-4253.
[20] G. P. Zhang, W. Hubner, E. Beaurepaire, and J. Y. Bigot. Experimental access to femtosecond spin dynamics [A]. See by Spin Dynamics in Condensed Magnetic Structures I, Hillebrands B, Ounadjela K (Eds.), Topics Appl. Phys., 2002, 83: 245.
[21] B. Koopmans, M. van Kampen, J. T. Kohlhepp, and W. J. M. de Jonge. Ultrafast magneto-optics in nickel; magnetism or optics? [J]. Phys. Rev. Lett., 2000, 85: 844-847.
[22] A. V. Kimel, A. Kirilyuk, P. A. Usachev, R. V. Pisarev, A. M. Balbashov and Th. Rasing. Ultrafast non-thermal control of magnetization by instantaneous photomagnetic pulses [J]. Nature, 2005,435: 655-657.
[23] J.Y.Bigot, J.C.Merle, O.Cregut, and A.Daunois. Electron Dynamies in Copper Metallic NanoParticles Probed with Femtosecond Optical Pulses. [J] Physical Review Letters, 1995, 75 (25): 4702-4705.
[24] T.V.Shahbazyan, I.E.Perakis, and J.Y.Bigot. Size dependent surface Plasmon dynamics in metal nanoparticles. [J] Physical Review Letters, 1998, 81(15): 3120-3123.
[25]A.Arbouet, C.Voisin, D.Christofilos, P.Ungot, N.DelFatti, F.Vallee, J.Urme, GCeleP, E. Cottanein, M.Gaudry, M.Pellarin, M.Broyer, M.Maillard, M.P.Pileni, and M.Treguer. Electron-phonon scattering in metal clusters. [J] Physical Review Letters, 2003, 90(17): 177401.
[26]Y.ohko, T.Tatsuma, T.Fujii, K.Naoi, C.Niwa, Y.Kubota, and A.Fujishima. Multicolour photochromism of TiO2 films loaded with silver nanoparticles. [J] Nature Materials, 2003, 2(1): 29-31.
[27] M.S.Hu, H.L.Chen, C.H.Shen, L.H.Hong, B.R.Huang, K.H.Chen, and L.C.Chen. Photosensitive gold-nanoparticle-embedded dielectric nanowires [J] Nature Materials, 2006, 5(2): 102-106.
[28] S.I.Anisimov et al. Structure of an absorption under the action of laser radiation on metal. [J] Sov. Phys. JETP, 1975, 39:375-380.
[29] S.Eustis and M.A.El-Sayed. Why gold nanoparticles are more precious than pretty gold: Noble metal surface Plasmon resonance and its enhancement of the radiative and nonradiative Properties of nanocrystals of different shapes. Chemical Soeiety Reviews, [J] 2006, 35(3):209-217.
[30] U.Kreibig and M.Vollmer. Optical Properties of Metal Clusters. [M] Berlin:Springer, 1995.
[31] C. D. Stanciu, F. Hansteen, A. V. Kimel, A. Kirilyuk, A. Tsukamoto, A. Itoh, and Th. Rasing. All-Optical Magnetic Recording with Circularly Polarized Light. [J] Phys.Rev.Lett.2007,99:047601.
[32]R.D.Averitt,S.L.Westcott,and N.J.Halas,Ultrafast electron dynamics in gold nanoshells[J]Phys.Rev.B 1998,58:R10203-R10206.
[2]查超麟.L1_(0)FePt基磁记录介质材料的研究[D],上海:复旦大学,2006.
[3]E.Beaurepaire,J.C.Merle,A.Daunois,and J.Y.Bigot.Ultrafast spin dynamics in ferromagnetic nickel[J].Phys.Rev.Lett.,1996,76:4250-4253.
[4]J.M.Kikkawa and D.D.Awschalom.All-optical magnetic resonance in semiconductors[J].Science,2000,287:473-476.
[5]J.A.Gupta,R.Knobel,N.Samarth,and D.D.Awschalom.Ultrafast manipulation of electron spin coherence[J].Science,2001,292:2458-2461.
[6]G.Ju,A.Vertikov,A.V.Nurmikko,C.Canady,G.Xiao,R.F.C.Farrow,and A.Cebollada.Ultrafast nonequilibrium spin dynamics in a ferromagnetic thin film[J]. Phys.Rev.B,1998,57:R700-R703.
[7]T.Kampfrath,R.G.Ulbrich,F.Leuenberger,M.Munzenberg,B.Sass and W.Felsch.Ultrafast magneto-optical response of iron thin films[J].Phys.Rev.B,2002,65:104429-1-6.
[8]P.Gr(u|¨)nberg,R.Schreiber,Y.Pang,M.B.Brodsky and H.Sowers.Layered Magnetic Structures:Evidence for Antiferromagnetic Coupling of Fe Layers across Cr Interlayers[J].Phys.Rev.Lett.1986,57:2442-2445.
[9]Bin Lu.Data Storage Overview[R].上海:复旦大学光科学与工程系,2004.
[10]P.J.Grundy,Thin film magnetic recording media[J].J.Phys.D:Appl.Phys.,1998,31:2975-2990.
[11]D.A.Thompson,J.S.Best,The future of magnetic data storage technology[J],IBM J.RES.DEVELOP.,2000,44(3):311-322.
[12]Y.Sonobe,H.Muraoka,K.Miura,and Y.Nakamura,et al.,Coupled granular/continuous perpendicular recording media with soft magnetic underlayer[J].J.Appl.Phys.,2002,91:8055-8057.
[13]H.Nakagawa,H.Nakagawa,H.Nemoto,Y.Honda,T.Ichihara,K.Tanahashi,and Y.Hosoe.Thermal stability and recording characteristics of TbCo/CoCrPt-hybrid media for perpendicular recording[J].J.Appl.Phys.,2002,91:8016-8018.
[14]Jian-Ping Wang,Weikang Shen,Jianmin Bai.Exchange coupled composite media for perpendicular magnetic recording[J].IEEE Trans.Magn.,2005,41:3181-3186.
[15]Jian-Ping Wang,W.K.Shen,J.M.Bai,et al.Composite media(dynamic tilted media)for magnetic recording[J],Appl.Phys.Lett.2005,86:142504:1-3.
[16]Mark H.Kryder,Future Materials Research in Data Storage[R]USA.NSF Workshop(2006)
[17]Shouheng Sun,C.B.Murray,Dieter Weller,Liesl Folks,Andreas Moser,Science 2000,Vol.287.no.5460,pp.1989-1992
[18]J.Y.Bigot.Femtosecond magneto-optical processes in metals[J].C.R.Acad.Sci.,2001,2:1483-1504.
[19]Bloch F.Nuclear Induction[J].Phys.Rev.1946,70:460-474.
[20]L.Landau,and L.Lifshitz.On the theory of the dispersion of magnetic permeability in ferromagnetic bodies[J].Phys.Z.Sowjetunion,1935,8:153.
[21]T.L.Gilbert.A Lagrangian Formulation of the Gyromagnetic Equation of the Magnetization Field[J].Phys.Rev.,1935,100:1243.
[22] J. Ferr(?), V. Grolier, P. Meyer, S. Lemerle, A. Maziewski, E. Stefanowicz, S. V. Tarasenko, V. V. Tarasenko, M. Kisielewski, and D. Renard. Magnetization-reversal processes in an ultrathin Co/Au film [J]. Phys. Rev. B, 1997, 55: 15092-15102.
[23] M. B. Agranat, S. I. Ashikov, A. B. Granovskii, and G. I. Rukman. Interaction of picosecond laser pulses with the electron, spin and phonon subsystem of nickel [J]. Sov. Phys. JETP, 1984, 59: 804-806.
[24] A. Vaterlaus, T. Beutler, and F. Meier. Spin-lattice relaxation time of ferromagnetic gadolinium determined with time-resolved spin-polarized photoemission [J]. Phys. Rev. Lett., 1991, 67: 3314-3317 .
[25] A. Vaterlaus, T. Beutler, D. Guarisco, M. Lutz, and F. Meier. Spin-lattice relaxation in ferromagnets studied by time-resolved spin-polarized photoemission [J]. Phys. Rev. B, 1992,46: 5280-5286.
[26] J. Hohlfeld, E. Matthias, R. Knorren, and K. H. Bennemann. Nonequilibrium magnetization dynamics of nickel [J]. Phys. Rev. Lett. 1997, 78: 4861-4864.
[27] J. Gudde, U. Conrad, V. Jahnke, J. Hohlfeld, and E. Matthias. Magnetization dynamics of Ni and Co .lms on Cu(001) and of bulk nickel surfaces [J]. Phys. Rev. B, 1999,59:R6608-R6611.
[28] J. Hohlfeld, J. Gudde, U. Conrad, O. Duhr, G Korn, and E. Matthias. Ultrafast magnetization dynamics of nickel [J]. Appl. Phys. B, 1999, 68: 505-510.
[29] A. Scholl, L. Baumgarten, R. Jacquemin, and W. Eberhardt. Ultrafast spin dynamics of ferromagnetic thin films observed by femtosecond spin-resolved two photon photemission [J]. Phys. Rev. Lett., 1997, 79: 5146-5149.
[30] U. Conrad, J. Gudde, V. Jahnke, and E. Matthias. Ultrafast magnetization and electron dynamics of thin Ni and Co films on Cu(001) observed by time-resolved SHG [J]. Appl. Phys. B, 1999, 68: 511-517.
[31] J. Hohlfeld. Utrafast electron, lattice and spin dynamics in metals: Investigated by linear and nonlinear optical techniques [D]. Ph.D. Thesis, Berlin: Freie University,, 1998.
[32] M. Aeschlimann, M. Bauer, S. Pawlik, W. Weber, R. Burgermeister, D. Oberli, and H.C. Siegmann. Ultrafast spin-dependent electron dynamics in fcc Co [J]. Phys. Rev. Lett., 1997, 79: 5158-5161.
[33] R. Knorren, K. H. Bennemann, R. Burgermeister, and M. Aeschlimann. Dynamics of excited electrons in copper and ferromagnetic transition metals: Theory and experiment [J]. Phys. Rev. B, 2000, 61: 9427-9440.
[34] E. Beaurepaire, M. Maret, V. Halte, J. C. Merle, A. Daunois, and J. Y. Bigot. Spin dynamics in CoPt3 alloy films: A magnetic phase transition in the femtosecond time scale [J]. Phys. Rev. B, 1998, 58:12134-12137.
[35] J. Hohlfeld, T. Gerrits, M. Bilderbeek, T. Rasing, H. Awano, and N. Ohta. Fast magnetization reversal of GdFeCo induced by femtosecond laser pulses [J]. Phys. Rev. B, 2001, 65: 012413:1-4.
[36] G. Ju, A. Vertikov, A.V. Nurmikko, C. Canady, G. Xiao, R. F. C. Farrow, and A. Cebollada. Ultrafast nonequilibrium spin dynamics in a ferromagnetic thin film, [J] Phys. Rev. B, 1998, 57: R700-R703.
[37] T. Kise, T. Ogasawara, M. Ashida, Y. Tomioka, Y. Tokura, and M. Kuwata-Gonokami. Ultrafast spin dynamics and critical behavior in half-metallic ferromagnet: Sr2FeMoO6 [J]. Phys. Rev. Lett., 2000, 85: 1986-1989.
[38] B. Koopmans, M. van Kampen, J. T. Kohlhepp, and W. J. M. de Jonge. Ultrafast magneto-optics in nickel; magnetism or optics? [J]. Phys. Rev. Lett., 2000, 85: 844-847.
[39] B. Koopmans, M. van Kampen, J. T. Kohlhepp, and W. J. M. de Jonge. Experimental access to femtosecond spin dynamics [J]. J. Phys.: Condens. Matt., 2002, 14: 1-14.
[40] B. Koopmans, M. van Kampen, J. T. Kohlhepp, and W. J. M. de Jonge. Femtosecond spin dynamics of epitaxial Cu(111)/Ni/Cu wedges [J]. J. Appl. Phys., 2000, 87: 5070-5072.
[41] B. Hillebrands, and K. Ounadjela (Eds.). Spin Dynamics in Confined Magnetic Structures II [M]. Topics Appl. Phys. 2003, 87: 253-320.
[42] B. Sinkovic, L. H. Tjeng, N. B. Brookes, J. B. Goedkoop, R. Hesper, E. Pellegrin, F. M. F. de Groot, S. Altieri, S. L. Hulbert, E. Shekel, and G A. Sawatzky. Local Electronic and Magnetic Structure of Ni below and above T_c: A spin-resolved circularly polarized resonant photoemission study [J]. Phys. Rev. Lett., 1997, 79: 3510-3513.
[43] T. J. Kreutz, T. Greber, P. Aebi, and J. Osterwalder. Temperature-dependent electronic structure of nickel metal [J]. Phys. Rev. B, 1998, 58: 1300-1317.
[44] M. Farle. Ferromagnetic resonance of ultrathin metallic layers [J]. Prog. Rep. Phys., 1998, 61:755-826.
[45] G. Ju, A.V. Nurmikko, R. F. C. Farrow, R. F. Marks, M. J. Carey, and B. A. Gurney. Coherent magnetization rotation by optical modulation in ferromagnetic /antiferromagnetic exchange-coupled bilayers[J].Phys.Rev.B,2000,62:1171-1177.
[46]G Ju,A.V Nurmikko,R.F.C.Farrow,R.F.Marks,M.J.Carey,and B.A.Gumey.Ultrafast optical modulation of an exchange biased ferromagnetic /antiferromagnetic bilayer[J].Phys.Rev.B,1998,58:R11857-R11860.
[1]张以忱,真空工艺与实验技术[M].北京:冶金工业出版社,2006.
[2]张树林,真空技术物理基础[M].沈阳:东北工学院出版社,1988.
[3]杨乃恒,真空获得设备.第二版[M].北京:冶金工业出版社,2001.
[4]彭勇,硕士毕业论文[D].兰州:兰州大学,2001.
[5]赵宝升,真空技术[M].北京:科学出版社,1998.
[6]郑伟涛,薄膜材料与薄膜技术[M].北京:化学工业出版社,2004.
[7]杨邦朝,王文生.薄膜物理与技术[M].北京:电子科技大学出版社,1994.
[8]吴自勤,王兵.薄膜生长[M].北京:科学出版社,2001.
[9]唐伟忠,薄腊材料制备原理、技术及应用(第2版)[M].北京:冶金工业出版社,2003.
[10]田民波,刘德令.薄膜科学与技术手册[M].北京:机械工业出版社,1991.
[11]王力衡,黄运添,郑海涛.薄膜技术[M].北京:清华大学出版社,1991.
[12]S.Jeon.Structure and magnetic properties of polycrystalline FePt and CoPt thin films for high density recording media[D],USA,PA:Carnegie Mellon University,2002.
[13]Warren B.E.,X-ray diffraction[M]Dover,New York,1990:208
[14]黄孝瑛,透射电子显微学[M].上海:上海科学技术出版社,1987.
[15]佚名.大唐网资料库[EB/OL].http://info.datang.net/ZF/ZF0056.htm,2004-1-1.
[16]X.M.Ding,X.Yang,and W.Xun,Surface physics and surface analysis [M].Shanghai,Fudan University,2007.
[17]周文生.磁性测量原理[M]北京:电子工业出版社,1988.
[18]Berger L,Bergmann G,Chien C L,et al,The Hall Effect and Its Applications[M].New York:Plenum,1979:55.
[19]Karplus R,Luttinger J M,Hall Effect in Ferromagnetics[J],Phys.Rev.,1954,95(5):1154-1160.
[20]Smit J,The spontaneous hall effect in ferromagnetics Ⅱ.Physica (Utrecht)[M],1958,24:39-51.
[21]R.M.Osgood,S.D.Bader,B.M.Clemens,R.L.White and H.Matsuyama.Second-order magneto-optic effects in anisotropic thin films[J].J.Magn.Man.Mater.,1998,182:297-323.
[22]M.Thomas.Faraday Diary[M].Londan,ibid,1845:7437-7444.
[23]白春礼,田芳,罗克.扫描力显微术[M].北京:科学出版社,2000.
[24]G.L.Eesley.Observation of Nonequilibrium Electron Heating in Copper[J].Phys.Rev.Lett.,1983,51:2140-2143.
[25]J.Hohlfeld,J.Gudde,U.Conrad,O.Duhr,G.Korn and E.Matthias.Ultrafast magnetization dynamics of nickel[J].Applied Physics B Lasers and Optics,1999,68,3:505-510.
[1]J.Zhou,R.Skomski,and X.Z.Li et al.Permanent-magnet properties of thermally processed FePt and FePt-Fe multilayer films[J],IEEE Trans.Magn.,2002,38:2802-2804.
[1]S.Iwasaki,Y.Nakamura,An analysis for the magnetization mode for high density magnetic recording[J]IEEE Trans.Magn.Mag.1977,13:1272-1277.
[2]S.Iwasaki,Y.Nakamura,K.Ouchi,Perpendicular magnetic recording with a composite anisotropy film[J]IEEE Trans.Magn.Mag.1979,15:1456-1458.
[3]Z.Xu,H.N.Hu,S.M.Zhou,S.L.Ren,X.X.Zhang.Combined effects of heat treatment and seed layer materials on magnetic properties of CoCrPt perpendicular media[J]Thin Solid Films 2008,516:2071-2077.
[4]G.M.Chow,C.J.Sun,E.W.Soo,J.P.Wang,H.H.Lee,D.Y.Noh,T.S.Cho,J.H.Je,Y.K.Hwu,Structural study of CoCrPt films by anomalous x-ray scattering and extended x-ray absorption fine structure[J]Appl.Phys.Lett.2002,80:1607-1609.
[5]Pawel Glijer,John M.Sivertsen,and Jack H.Judy.Effects of platinum content and substrate bias on the structure and magnetic properties of CoCrPt/Cr thin films[J]J.Appl.Phys.1993,73:5563-5565.
[6]A.Sato,S.Nakagawa,M.Naoe,Co-Cr-Ta Perpendicular Magnetic Recording Media Using Pt Seed Layer[J]IEEE Trans.Magn.2000,36:2387-2389.
[7]S.Saito,N.Itagaki,M.Takahashi,Improvement of perpendicular magnetic properties by postannealing for M'-CoCrPt-M stacked media(M,M'=Ti,Ta,Ru,Pt,CrMn,MnSi)[J]IEEE Trans.Magn.2004,40:2467-2469.
[8]P.W.Jiang,S.Y.Hong,J.Y.Kim,Role of Ag seed layer for CoCrPt/Ti perpendicular recording media[J]J.Appl.Phys.2003,93:7741-7743.
[9]A.G.Roy,D.E.Laughlin,Effect of seed layers in improving the crystallographic texture of CoCrPt perpendicular recording media[J]J.Appl.Phys.2002,91:8076-8078.
[10]Y.J.Kim,W.H.Park,S.H.Kong,S.Nakagawa,K.H.Kim,Improvement of c-axis preferred orientation of CoCr-based thin film with amorphous Si underlayer[J]Surf.Coat.Technol.2003,532:169-170.
[11]M.H.Hu,S.Noda,H.Komiyama,Amorphous-to-crystalline transition during the early stages of thin film growth of Cr on SiO_2[J]J.Appl.Phys.2003,93:9336-9344.
[12]高铁仁 垂直磁记录介质的制备及物性研究[D],上海:复旦大学,2006.
[1]Zhen Xu,Shiming Zhou,JJ Ge,Jun Du,Li Sun Magnetization reversal mechanism of perpendicularly exchange-coupled composite L10-FePt/CoCrPt bilayers[J].accepted by J.Applied Physics,2009.
[2]R.H.Victora and X.Shen,Composite media for perpendicular recording[J].IEEE Trans.Magn.2005,41:537-542.
[3]D.Suess,T.Schrefl,R.Dittrich,M.Kirschner,F.Dorfbauer,G.Hrkac,and J.Fidler,Exchange spring recording media for areal densities up to 10 Tbit/in~2[J].J.Magn.Magn.Mater.2005,290:551-554.
[4] A. Y. Dobin and H. J. Richter, Domain wall assisted magnetic recording [J]. Appl. Phys. Lett. 2006, 89: 062512:1-3.
[5] M. Ghidini, G. Asti, R. Pellicelli, C. Pemechele, and M. Solzi, Hard-soft composite magnets [J]. J. Magn. Magn. Mater. 2007,316: 159-165.
[6] H. Kronmiiller and D. Goll, Pinning of domain walls in composite particles [J]. Physica B 2008,403: 237-241.
[7] D. Suess, Micromagnetics of exchange spring media: Optimization and limits [J]. J. Magn. Magn. Mater. 2007, 308: 183-197.
[8] B. Livshitz, A. Inomata, H. N. Bertram, and V. Lomakin, Precessional reversal in exchange-coupled composite magnetic elements [J]. Appl. Phys. Lett. 2007, 91: 182502:1-3.
[9] D. Goll, S. Macke, and H. N. Bertram, Thermal reversal of exchange spring composite media in magnetic fields [J]. Appl. Phys. Lett. 2007, 90: 172506:1-3.
[10] E. E. Fullerton, J. S. Jiang, M. Grimsditch, C. H. Sowers, and S. D. Bader, Exchange-spring behavior in epitaxial hard/soft magnetic bilayers [J]. Phys. Rev. B 1998, 58: 12193-12200.
[11] J. E. Davies, O. Hellwig, E. E. Fullerton, J. S. Jiang, S. D. Bader, G T. Zimanyi, and K. Liu, Anisotropy dependence of irreversible switching in Fe/SmCo and FeNi/FePt exchange spring magnet films [J]. Appl. Phys. Lett. 2005, 86: 262503:1-3.
[12] A. J. Zambano, H. Oguchi, I. Takeuchi, Y. Choi, J. S. Jiang, J. P. Liu, S. E. Lofland, D. Josell, and L. A. Bendersky, Dependence of exchange coupling interaction on micromagnetic constants in hard/soft magnetic bilayer systems [J]. Phys. Rev. B 2007, 75: 144429:1-7.
[13] Y. Choi, J. S. Jiang, J. E. Pearson, S. D. Bader, J. J. Kavich, J. W. Freeland, and J. P. Liu, Controlled interface profile in Sm-Co/Fe exchange-spring magnets [J]. Appl. Phys. Lett. 2007, 91: 072509:1-3.
[14] J. P. Wang, W. Shen, and S. Y. Hong, Fabrication and Characterization of Exchange Coupled Composite Media [J]. IEEE Trans. Magn. 2007, 43: 682-686.
[15] D. Goll, A. Breitling, and S. Macke, Magnetic Properties of Exchange-Coupled L1_0-FePt/Fe Composite Elements [J]. IEEE Trans. Magn. 2008, 44: 3472-3475.
[16] D. Goll, A. Breitling, L. Gu, P. A. van Aken, and W. Sigle Experimental realization of graded L1_0-FePt/Fe composite media with perpendicular magnetization [J]. J. Appl. Phys. 2008,104: 083903:1-4.
[17] F. Casoli, F. Albertini, S. Fabbrici, C. Bocchi, L. Nasi, R. Ciprian, and L.Pareti, Exchange-coupled FePt/Fe bilayers with perpendicular magnetization [J]. IEEE Trans. Magn. 2005,41: 3877-38779.
[18] D. Goll and A. Breitling, Coercivity of ledge-type L1_0-FePt/Fe nanocomposites with perpendicular magnetization [J]. Appl. Phys. Lett. 2009, 94: 052502:1-3.
[19] J. F. Hu, J. S. Chen, Y. F. Ding, B. C. Lim, W. L. Phyoe, and B. Liu Exchange coupling assisted FePtC perpendicular recording media [J]. Appl. Phys. Lett. 2008, 93: 072504:1-3.
[20] Hao Zeng, Jing Li, J. P. Liu, Zhong L. Wang and Shouheng Sun, Exchange-coupled nanocomposites magnets by nanoparticle self-assembly [J]. Nature 2002,420: 395-398.
[21] Yanglong Hou, Zhichuan Xu, Sheng Peng, Chuanbing Rong, J. Ping Liu, and Shouheng Su, A facile synthesis of SmCo_5 magnets from Core/Shell Co/Sm_2O_3 nanoparticles [J]. Advanced Materials, 2007,19: 3349-3352.
[22] Yanglong Hou, Shouheng Sun, Chuanbing Rong, and J. Ping Liu SmCo_5/Fe nanocomposites synthesized from reductive annealing of oxide nanoparticles [J]. Appl. Phys. Lett., 2007, 91: 153117:1-3.
[23] Chuan-bing Rong, Vikas Nandwana, Narayan Poudyal, J.P. Liu, Tetsuji Saito, Yaqiao Wu, and Matthew J. Kramer Bulk FePt/Fe3_Pt nanocomposite magnets prepared by spark plasma sintering [J]. J. Applied Physics, 2007,101: 09K515:1-3.
[24] R. Pellicelli, C. Pernechele, M. Solzi, M. Ghidini, F. Casoli, and F. Albertini, Modeling and characterization of irreversible switching and viscosity phenomena in perpendicular exchange-spring Fe-FePt bilayers [J]. Phys. Rev. B 1998, 78: 184434:1-10.
[25] R. Wood, Y. Sonobe, Z. Jin, and B. Wilson, Perpendicular recording: the promise and the problems [J]. J. Magn. Magn. Mater. 2001,235: 1-9.
[26] D. Weller, A. Moser, L. Folks, M. E. Best, W. Lee, M. F. Toney, M. Schwickert, J.-U. Thiele, and M. F. Doerner, High Ku materials approach to 100 Gbits/in~2 [J]. IEEE Trans. Magn. 2000, 36: 10-15.
[27] G. Asti, M. Ghidini, R. Pellicelli, C. Pernechele, M. Solzi, F. Albertini, F. Casoli, S. Fabbrici, and L. Pareti. Magnetic phase diagram and demagnetization processes in perpendicular exchange-spring multilayers [J]. Phys. Rev. B 2006, 73: 094406.
[28] J. P. Wang, W. K. Shen, J. M. Bai, R. H. Victora, J. H. Judy, and W. L. Song. Composite media(dynamic tilted media) for magnetic recording [J]. Appl. Phys. Lett. 2005, 86: 142504.
[29] D. Golla and S. Macke, Thermal stability of ledge-type L10-FePt/Fe exchange-spring nanocomposites for ultrahigh recording densities, [J]. Appl. Phys. Lett. 2008, 93: 152512.
[30] Vitaliy Lomakin, Richard Choi, Boris Livshitz, Shaojing Li, Akihiro Inomata, and H. Neal Bertram, Dual-layer patterned media "ledge" design for ultrahigh density magnetic recording. [J]. Appl. Phys. Lett. 2008, 92: 022502.
[31] C. Byun, J. M. Sivertsen, and J. H. Judy. A study on magnetization reversal mechanisms of CoCr films, [J]. IEEE Trans. Magn. 1986,22: 1155-1157.
[32] D. Givord, P. Tenaud, and T. Viadieu, Angular dependence of coercivity in sintered magnets [J]. J. Magn. Magn. Mater. 1988, 72: 247-252.
[33] X. M. Cheng, S. Urazhdin, O. Tchernyshyov, C. L. Chien, V. I. Nikitenko, A. J. Shapiro, and R. D. Shull, Antisymmetric Magnetoresistance in Magnetic Multilayers with Perpendicular Anisotropy [J]. Phys. Rev. Lett. 2005, 94: 017203.
[34] F. Garcia-Sanchez, O. Chubykalo-Fesenko, O. Mryasov,P. Asselin, and R. W. Chantrell, Switching and thermal stability properties of bilayer thin films: Single versus multigrain cases [J]. J. Appl. Phys. 2008,103: 07F505.
[1]Massalski T.Binary alloy phase diagrams[M].2nd Edition.Ohio:Metals Park,1990.
[2]Y.K.Takahashi,T.Koyama,M.Ohnuma,T.Ohkubo,and K.Hono,Size dependence of ordering in FePt nanoparticles[J]J.Appl.Phys.2004,95:2690-2696.
[3]Platt,CL;Wierman,KW;Svedberg,EB,et al.L10 ordering and microstructure of FePt thin films with Cu,Ag,and Au additive[J].J Appl Phys,2002,92:6104-6109.
[4]Yan M L,Sabirianov R F,Xu Y F,et al,L10 ordered FePt:C composite films with[001]texture[J].IEEE Trans Magn,2004,40:2 47022.
[5]Luo C P,Liou S H,Gao L,et al,Nanostructured FePt:B203 thin films with perpendicular magnetic anisot ropy[J].Appl Phys Lett,2000,77:2225-2227.
[6]Kim H J,Lee S R.Texture development and magnetic properties of sputter deposited FePt MgO nanocomposite films[J].J Appl Phys,2005,97:10H304.
[7] Sakurai R, Yamamoto Y, Chen C , et al , Structure and magnetic behavior of reactive sputter deposited nanocomposite FePtTiN films [J] . Thin Solid Films , 2004,459:208-211.
[8] Bai J , Yang Z , Wei F , et al. Nanocomposite FePtA12O3 films for high2density magnetic recording [J ] J Magn Magn Mater, 2003 ,257: 132-137
[9] Daniil M , Farber P A , Okumura H , et al. FePt/ BN granular films for high density recording media [J] J Magn Magn Mater, 2002 ,246: 297-302.
[10] H.R.Hulme, [C] Proc.R.Soc.London, Ser.A 1932,135: 237.
[11] C.Kittel, Optical rotation by ferromagnetic substances [J] Phys.Rev. 1951, 83: 208-210.
[12] P.N.Argyres, Theory of the Faraday and Kerr Effects in Ferromagnetics [J] Phys.Rev. 1955, 97: 334-345.
[13] G.Y. Guo, H. Ebert. On the origins of the enhanced magneto-optical Kerr effect in ultrathin Fe and Co multilayers[J],Journal of Magnetism and Magnetic Materials 1996,156: 173-174.
[14] L. Uba, S. Uba, V. N. Antonov, A. N. Yaresko, and R. Gontarz. Microscopic origin of the magneto-optical properties of CoPt alloys [J].Phys. Rev. B 2001, 64: 125105.
[15] Till, Burkert, Olle, Eriksson, Sergei, I. Simak, Andrei, V. Ruban, Biplab, Sanyal, Lars, Nordstrom, and John, M. Wills, Magnetic anisotropy of L1_0 FePt and Fe_(1-x)Mn_xPt [J] Physical Review B 2005, 71: 134411.
[16] Brown, G., Kraczek, B., Janotti, A., Schulthess, T. C., Stocks, G. M., and Johnson, D. D., Competition between ferromagnetism and antiferromagnetism in FePt [J] Physical Review B 2003, 68: 052405.
[17] Staunton, J. B., Ostanin, S., Razee, S. S. A., Gyorffy, B. L., Szunyogh, L., Ginatempo, B., and Ezio, Bruno, Temperature Dependent Magnetic Anisotropy in Metallic Magnets from an Ab Initio Electronic Structure Theory: L1_0-Ordered FePt [J] Physical Review Letters 2004, 93: 257204.
[18] Kitakami, Osamu, Okamoto, Satoshi, Kikuchi, Nobuaki, and Shimada, Yutaka, Energy Barrier Enhanced by Higher Order Magnetic Anisotropy Terms [J] Jpn J Appl Phys 2003, 42: L455 (part2).
[19] E. Beaurepaire, J. C. Merle, A. Daunois, and J. Y. Bigot. Ultrafast spin dynamics in ferromagnetic nickel [J]. Phys. Rev. Lett., 1996, 76: 4250-4253.
[20] G. P. Zhang, W. Hubner, E. Beaurepaire, and J. Y. Bigot. Experimental access to femtosecond spin dynamics [A]. See by Spin Dynamics in Condensed Magnetic Structures I, Hillebrands B, Ounadjela K (Eds.), Topics Appl. Phys., 2002, 83: 245.
[21] B. Koopmans, M. van Kampen, J. T. Kohlhepp, and W. J. M. de Jonge. Ultrafast magneto-optics in nickel; magnetism or optics? [J]. Phys. Rev. Lett., 2000, 85: 844-847.
[22] A. V. Kimel, A. Kirilyuk, P. A. Usachev, R. V. Pisarev, A. M. Balbashov and Th. Rasing. Ultrafast non-thermal control of magnetization by instantaneous photomagnetic pulses [J]. Nature, 2005,435: 655-657.
[23] J.Y.Bigot, J.C.Merle, O.Cregut, and A.Daunois. Electron Dynamies in Copper Metallic NanoParticles Probed with Femtosecond Optical Pulses. [J] Physical Review Letters, 1995, 75 (25): 4702-4705.
[24] T.V.Shahbazyan, I.E.Perakis, and J.Y.Bigot. Size dependent surface Plasmon dynamics in metal nanoparticles. [J] Physical Review Letters, 1998, 81(15): 3120-3123.
[25]A.Arbouet, C.Voisin, D.Christofilos, P.Ungot, N.DelFatti, F.Vallee, J.Urme, GCeleP, E. Cottanein, M.Gaudry, M.Pellarin, M.Broyer, M.Maillard, M.P.Pileni, and M.Treguer. Electron-phonon scattering in metal clusters. [J] Physical Review Letters, 2003, 90(17): 177401.
[26]Y.ohko, T.Tatsuma, T.Fujii, K.Naoi, C.Niwa, Y.Kubota, and A.Fujishima. Multicolour photochromism of TiO2 films loaded with silver nanoparticles. [J] Nature Materials, 2003, 2(1): 29-31.
[27] M.S.Hu, H.L.Chen, C.H.Shen, L.H.Hong, B.R.Huang, K.H.Chen, and L.C.Chen. Photosensitive gold-nanoparticle-embedded dielectric nanowires [J] Nature Materials, 2006, 5(2): 102-106.
[28] S.I.Anisimov et al. Structure of an absorption under the action of laser radiation on metal. [J] Sov. Phys. JETP, 1975, 39:375-380.
[29] S.Eustis and M.A.El-Sayed. Why gold nanoparticles are more precious than pretty gold: Noble metal surface Plasmon resonance and its enhancement of the radiative and nonradiative Properties of nanocrystals of different shapes. Chemical Soeiety Reviews, [J] 2006, 35(3):209-217.
[30] U.Kreibig and M.Vollmer. Optical Properties of Metal Clusters. [M] Berlin:Springer, 1995.
[31] C. D. Stanciu, F. Hansteen, A. V. Kimel, A. Kirilyuk, A. Tsukamoto, A. Itoh, and Th. Rasing. All-Optical Magnetic Recording with Circularly Polarized Light. [J] Phys.Rev.Lett.2007,99:047601.
[32]R.D.Averitt,S.L.Westcott,and N.J.Halas,Ultrafast electron dynamics in gold nanoshells[J]Phys.Rev.B 1998,58:R10203-R10206.