摘要
层状磁性材料具有轻、薄、短、小以及直接成型等特点,能充分满足小型电机和特种磁器件等要求,已成为当今高新技术发展的关键材料之一。磁学理论的发展与磁性材料的技术应用息息相关。其中,磁性材料中的相变温度和补偿温度在电机和磁光记录方面具有重要应用。本文选取两类层状混自旋磁性材料AFeⅡFeⅢ(C2O4)3和[NiCr2(bipy)2(C2O4)4(H2O)2]H2O为研究对象,从量子力学的微观理论出发,采用MonteCarlo方法,建立双子格混自旋Ising模型,详细研究了两类层状磁性材料的磁性质和热力学性质、表面效应以及阶梯效应等物理性质。论文主要内容包括以下几个方面:
针对两类层状磁性块体材料,研究了磁晶各向异性、交换耦合作用、温度以及纵场等对系统补偿温度和相变温度、磁矩、初始磁化率、磁滞回线、内能和比热的影响。探讨了补偿温度产生的原因和影响因素,并获得了相图。研究结果表明:子格磁晶各向异性和铁磁性层间交换耦合作用的增强都会稳定其子格的磁矩;热力学涨落会破坏系统子格磁矩的稳定性,削弱系统的磁有序;纵场会在磁场方向上稳定系统磁矩;磁矩曲线类型的变化来源于上述几种相互作用之间竟争的结果。纵场能够削弱系统的补偿行为。当取某些特定参数时,系统会呈现两环或三环形状的磁滞回线。两类系统的内能随温度升高而升高,并且磁晶各向异性、交换耦合作用以及纵场的增大都会使内能减小,而比热在相变点处出现奇异现象,纵场使比热曲线变得平缓。
针对两类层状磁性薄膜材料,研究了表面参数和层厚对系统磁性和热力学性质的影响。发现了补偿温度、相变温度及矫顽力保持不变的表面参数条件,建立了三维相图,获得了系统存在多个补偿点的表面参数范围。通过与实验结果比对,验证了计算结果的可靠性。研究结果表明:对于亚铁磁混自旋2和5/2系统,表面层内交换耦合作用和表面层间交换耦合作用对补偿温度的影响相反。而对于相变温度来说,二者的影响基本一致。由于表面效应和尺寸效应的共同作用,表面子格磁晶各向异性的增大有利于补偿现象的发生,并且层厚的改变也会使系统会出现多个补偿点的现象。由于两类系统结构的不同,补偿行为和相变规律也有所差异。对于双层亚铁磁混自旋1和3/2系统,并没有发现补偿温度不变的表面参数条件。
基于层状亚铁磁混自旋2和5/2系统在低温下所表现出的阶梯效应,探究了磁滞回线产生阶梯效应及形状变化的原因。研究结果表明:系统磁滞回线会表现出2S+1个磁性阶梯,其数量的变化反映了系统在基态或低温下自旋组态的变化。温度会削弱系统的阶梯效应,使磁滞回线的磁能积、矫顽力和剩磁都减小。
Layered magnetic materials have many characteristics such as light, thin, short, smalland direct forming so that they can fully meet small motors and special magnetic devices,and have become the key to the development of today's high-tech materials. Developmentof magnetism theory is closely linked with the technology application of magneticmaterials. The existences of the transition temperature and the compensation temperaturein magnetic materials have potential applications in electric motors and optical-magnetorecording. Selecting two kinds of layered mixed spin magnetic materials AFeⅡFeⅢ(C2O4)3and [NiCr2(bipy)2(C2O4)4(H2O)2]H2O, we set up the twin lattice mixed spin Ising modelsto study their magnetic and thermodynamic properties, surface effect and step effect byMonte Carlo simulation from the microscopic theory of quantum mechanics in thedissertation. The study contents are mainly as follows:
For two kinds of layered magnetic solid materials, the effects of the anisotropy, theexchange coupling, the temperature and the longitudinal magnetic field on thecompensation temperature and the transition temperature, the magnetization, the initialsusceptibility, the internal energy, the specific heat, the hysteresis loop and the coercivityof two systems are discussed. The causes and influence factors of the compensationtemperature are discussed, and the phase diagrams are obtained. The studied results showthat both the anisotropy and the interlayer ferromagnetic exchange coupling can stabilizethe magnetization of sublattice. The thermodynamic fluctuation makes the magnetic orderweakened, destroying the stability of the sublattice magnetization. The longitudinalmagnetic field can stabilize the longitudinal magnetization of the system. Suchmagnetization behaviors of the system are originating from the competition among abovethese effects. The longitudinal magnetic field can make the compensation behaviourweakened. For certain parameters, the double and triple hysteresis loops appear in the system. For two systems, the internal energy increases as the temperature increases, andthe anisotropy, the exchange coupling and the longitudinal magnetic field all can decreasethe internal energy. The specific heat exhibits the discontinuity at the transitiontemperature and become flatter for the larger longitudinal magnetic field.
For two kinds of magnetic thin film materials, the effects of the surface parametersand the layer thickness on the magnetic and thermodynamic properties of two systems arestudied. The surface parameter conditions where the compensation temperature, thetransition temperature and the coercivity remain constant are found, and thethree-dimensional phase diagrams are obtained. The surface parameter scopes of themultiple compensation points are discovered. Comparing with the experimental results, thereliability of our results is verified. The studied results show that: for the ferrimagneticmixed spin-2and spin-5/2Ising system, the effect of the surface intralayer exchangecoupling on the compensation temperature is opposite to that of the surface interlayerexchange coupling, whereas both effects on the transition temperature are same. Due to thecombined effects of surface and size, increasing the surface anisotropy can contribute tothe compensation behavior, and changing the layer thickness can also make the systemdisplay the multiple compensation points. Because of the differenent structure of two kindsof materials, the compensation behavior and phase transition rule are also different. For thedouble layer ferrimagnetic mixed spin-1and spin-3/2system, we have not found thesurface parameter condition where the compensation temperature remains constant.
Based on step effect in the layered ferrimagnetic mixed spin-2and spin-5/2system atlow temperature, the evolution and the change of the shape of the hysteresis loop arediscussed. Research results show that the2S+1magnetic plateaus appear in the hysteresisloop, which reveals the variation of spin configuration of the system at the ground state orlow temperature. The temperature weakens step effect and decreases magnetic energyproduct, the coercivity and the remanence of the hysteresis loop.
引文
[1]都有为.磁性材料进展.物理,2000,6:323~332.
[2]李跃华,杨志毅.分子基磁性材料的发展和展望.大理学院学报,2011,4(10):43~47.
[3] P. Langevin. On the theory of magnetism. J.Phys.Thero.Appl.,1905,4(1):678~693.
[4] M. S. Davis, K. Morokuma, R. W. Kreilick. Free radicals with large negative spin densities. J.Am.Chem. Soc.,1972,94(16):5588~5592.
[5] A. Zheludev, V. Barone, M. Bonnet, B. Delley, A. Grand, E. Ressouche, P. Rey, R. Subra, J.Schweizer. Spin density in a nitronyl nitroxide free radical. Polarized neutron diffractioninvestigation and ab initio calculations. J. Am. Chem. Soc.,1994,116(5):2019~2027.
[6]宛德福.磁性理论及其应用.武汉:华中理工大学出版社,1995.
[7] D. C. Vonsovskii. Magnetism. New York: John Wiley and Sons, Inc.,1974.
[8] S. Chikazumi. Physics of magnetism. New York: John Wiley and Sons, Inc.,1964.
[9] D. C. Mattis. The theory of magnetism I. Berlin: Springer-Verlag,1981.
[10]郭贻成.铁磁学.北京:人民教育出版社,1965.
[11] L. Néel. Magnetic properties of ferrites: ferrimagnetism and antiferromagnetism. Ann. Phys.,1948,(3):137~198.
[12] M. Connel, M. Harden. Ferromagnetism in Solid Free Radicals. J. Chem. Phys.,1963,39(3):1910~1918.
[13] H. H. Wickman, A. M. Trozzolo, H. J. Williams et al. Combinatorial approach to the ferroelectricproblem. Phys. Rev. B,1967,171(2):563~565.
[14] J. S. Miller, J. C. Calabrese, A. J. Epstein et al. Ferromagnetic properties of one-dimensionaldecamethylferrocenium tetracyanoethylenide (1:1):[Fe(n5-C5Me5)2].+[TCNE].–. J. Chem. Soc.Chem. Commun.,1986,13(1):1026~1028.
[15] J. M. Manriquez, G. T. Yee, R. S. Mclean et al. Room-temperature molecular/organic-basedmagnet. Science,1991,252(5011):1415~1417.
[16] M. Takahashi, P. Turek, M. Nakazawa et al. Discovery of a quasi-1D organic ferromagnetp-NPNN. Phys. Rev. Lett.,1991,67(6):746~748.
[17] Y. Pei, M. Verdauger, Kahno et al. Magnetism of manganese(II) copper(II) and nickel(II) copper(II)ordered bimetallic chains crystal structure of MnCu(pba)(H2O)3·2H2O (pba=1,3-propylenebis(oxamato)). Inorg. Chem.,1987,26(1):138~143.
[18] T. Mallah, S. Thiebaut, M. Verdaguer et al. Molecular-based magnet with two magnetic transitiontemperature: A prussian-blue analogue Mn3[Cr(CN)6]2·12H2O. Science,2007,262(5139):1554~1561.
[19] C. Mathoniere, C. J. Nuttall, S. G. Carling, and P. Day. Ferrimagnetic mixed-valency andmixed-Metal Tris(oxalato)iron(III) compounds: synthesis, structure, and magnetism. Inorg. Chem.,1996,35(5):1201~1205.
[20] M. Mansuripur.M6H6agnetization reversal coercivity and the process of thermomagnetic recording inthin films of amorphous rare earth-transition metal alloys. J. Appl. Phys.,1987,61(4):1580~1587.
[21] Y. Nakamura. Existence of a compensation of a mixed spin-2and spin-5/2Ising ferrimagneticsystem on a layered honeycomb lattice. Phys. Rev. B,2000,62(17):11742~11745.
[22] W. Jiang, C. Liu, Y. Jiang. Effects of transverse field on the magnetization and initial susceptibilityof a molecular-based magnet. Physica A,2008,387(18):4599~4604.
[23] W. Jiang, W. Wang, F. Zhang, W. J. Ren. Magnetic properties of a molecular-based magnetAFeIIFeIII(C2O4)3with biaxial crystal field. J. Appl. Phys.,2009,105(7):07E321~07E323.
[24] W. Jiang, V. C. Lo B. D. Bai, J. Yang. Magnetic hysteresis loops in molecular-based magneticmaterials. Physica A,2010,389(11):2227~2233.
[25] Y. Nakamura. Monte Carlo study of a mixed spin-2and spin-5/2Ising system on a honeycomblattice.J6H7ournal of Physics: Condensed Matter.,2000,12(17):4067~4077.
[26]程鹏,廖代正,王耕霖.多金属偶合体系的分子磁工程.化学通报,1994,40(2):9-15.
[27] A.Caneschi, D.Gatteschi. The chemistry and magnetic properties of metal nitronyl nitroxidecomplexes. Inorg Chem,1991,39(3):331~429.
[28] G. Srinivasan, B. U. M. Rao, J. Zhao, M. S. Seehra. Magnetically ordered amorphous copper ferrite.Appl. Phys. Lett.,1991,59(3):372~374.
[29] R. C. O’Handley. Modern magnetic principles and applications, New York: John Wiley,2000.
[30]白木,周洁.纳米磁性材料及其应用.信息记录材料,2002,3(2):38~39.
[31]余声明.蓬勃发展中的磁性薄膜材料.国际电子变压器,2009,10(1):97~101.
[32] A. J. Freeman, R. Wu, Magnetism in man made materials. J. Magn. Magn. Mater.,1992,104-107(6):1~6.
[33] P. Grnberg, R. Schreiber, Y. Pang et al. Layered magnetic structures: evidence forantiferromagnetic coupling of Fe layers across Cr interlayers. Phys. Rev. Lett.,1986,57(19):2442~2445.
[34] M. Vohl, J. Barnas, P. Grunberg. Effect of interlayer exchange coupling on spin wave spectra inmagnetic double layer: theory and experiment. Phys. Rev. B,1989,39(16):12003~12012.
[35] A. Moshel, K. D. Usadel, A. Hucht. Magnetization of ferromagnetic-antiferromagnetic doublelayers. Phys. Rev. B,1993,47(14):8676~8680.
[36] B. Hillebrands. Spin-wave calculations for multilayered structures. Phys. Rev. B,1990,41(1):530~540.
[37] A. J. Freeman, R.Q. W. Magnetism in man-made materials. J. Magn. Magn. Mater.,1992,104(2):1~6.
[38] M. Taborelli, R. Allenspach, G. Boffa et al. Magnetic coupling of surface layers: Gd on Fe(100).Phys. Rev. Lett.,1986,56(26):2869~2872.
[39] H. Matsuyama, C. Haginoya, K. Koike. Microscopy imaging of Fe magnetic domains exchangecouple with those in a NiO(001) surface. Phys. Rev. Lett.,2000,85(11):646~649.
[40] M. J. Carey, A. E. Berkowitz, J. A. Borchers et al. Strong interlayer coupling in CoO/NiOantiferromagnetic superlattices. Phys. Rev. B,1993,47(15):9952~9955.
[41] Y. Ijiri, J. A. Borchers, R. W. Erwin et al. Perpendicular coupling in exchange-biased Fe3O4/CoOsuperlattices. Phys. Rev. Lett.,1998,80(3):608~611.
[42]N. E. Aouad, B. Laaboudi, M. Kerouad et al. Phase transition properties of a ferroelectric spin-1/2Ising superlattice. J. Phys.:Condens Matter.,2001,3(5):797-809.
[43]邱荣科,梁静.双层亚铁磁体超晶格的能谱.沈阳工业大学学报,2007,29(5):507-512.
[44]A. Du, Y. Ma, Z. H. Wu. Magnetization and magnetic susceptibility of the ising ferromagnetic/antiferromagnetic superlattice. J. Magn. Magn. Mat.,2006,305(1):233-239.
[45]W. Jiang, B. D. Bai. Hysteresis loops and susceptibility of ferromagnetic or ferrimagnetic bilayer system, phys. stat. sol.(b),2006,243(12):2892-2900.
[46]E. Cesur. Influence of anisotropic crystal field on a ferrimagnetic mixed-spin bilayer system. Physica A,2008,387(5-6):1185-1199.
[47]T. Kaneyoshi. Phase diagrams of a transverse Ising bilayer system. J. Magn. Magn. Mater.,2001,226-230(2):1746-1748.
[48]T. Kaneyoshi. Phase diagrams of a bilayer system in a transverse filed. phys. stat. sol.(b),2000,220(2):951-958.
[49]T. Kaneyoshi, S. Shin. Critical properties of a spin-1/2Ising bilayer system in a transverse field. phys. stat. sol.(b),2000,218(2):537-544.
[50]M. Jascur, T. Kaneyoshi. Compensation temperature in a ferromagnetic multilayer system with disordered interfaces and its thickness dependence. phys. stat. sol.(b),1997,203(2):507-515.
[51]M. Jascur, T. Kaneyoshi. The effect of anisotropies on the transition temperature in a spin-1/2and spin-3/2bilayer system with disordered interfaces. Physica A,1995,220(3):542-551.
[52]T. Kaneyoshi. Role of applied transverse field in a ferromagnetic bilayer system with disordered interfaces. Phys. Rev. B,1995,52(10):7304-7307.
[53]T. Kaneyoshi. The relation between compensation temperature and anisotropy in a ferrimagnetic bilayer system with disordered interfaces. Solid State Commun.,1995,93(8):691-695.
[54]T. Kaneyoshi. The magnetic properties of a ferrimagnetic bilayer system with disordered interfaces. J. Phys.:Condens Matter,1994,6(49):10691-10703.
[55]P. Tomczak. Magnetic phase transitions in the Ising superlattice with interfaces. J. Magn. Magn. Mater.,1989,78(3):403-411.
[56]A. Saber, H. E. Zahraouy, R. S. Lo et al. Phase diagrams of a spin-1Ising superlattice with alternating transverse field. J. Magn. Magn. Mater.,2003,(261):78-87.
[57]A. Oubelkacem, N. E. Aouad, A. Benaboud, M. Saber. The phase diagrams and the order parameters of the diluted superlattice with antiferromagnetic interface coupling. J. Magn. Magn. Mater.,2004,279(2-3):270-285.
[58]Stanican, C. V. Stager, M. Cimpoesu et al. Synthesis and magnetic properties of a new oxalato-bridged heterotrinuclear complex [NiCr2(bipy)2(C2O4)4(H2O)2]·H2O. A rare case of antiferro-magnetic coupling between CrⅢ and NiⅡ ions. Polyhedron,1998,17(10):1787-1789.
[59]D. Bayram, A. K. Salih, K. Mustafa. Mixed spin-1and spin-3/2Ising system with two alternative layers of a honeycomb lattice within the effective-field theory. Solid State Communications,2011,1(51):193-198.
[60]刘国征,夏宁,刘小鱼,赵明静,赵瑞金.稀土磁性功能薄膜材料的研究现状.稀土,2010,31(1):86-91.
[61]陈庆祺,何志伟.小功率电机在国内外的发展概况.电机电器技术,2004,(1):25-26.
[62]唐任远.稀土永磁电机的关键技术与高性能电机开发.沈阳工业大学学报,2005,27(2):162-170.
[63]冯瑞华,姜山,马廷灿,万勇.我国稀土永磁材料发展战略和建议.科技管理研究,2012,(15):164-167.
[64]徐阳.用途广泛的新型磁性材料.电子技术应用,2003,(3):1-2.
[65]马廷钩.磁光存储技术及其近期发展.现代物理知识,1995,(4):25-26.
[66]张志东.伊辛模型的研究进展简介.自然杂志,2008,30(2):94-98.
[67]A. P. Vieira, J. X. de Carvalho, S. R. Salinas. Phase diagram of a random-anisotropy mixed-spin Ising model. Phys. Rev. B,2001,63(18):184415-1-184415-7.
[68]G. M. Zhang, C. Z. Yang. Monte Carlo study of the two-dimensional quadratic Ising ferromagnet with spins S=1/2and S=1and with crystal-field interactions. Phys. Rev. B,1993,(13):9452-9455.
[69]G. M. Buendia, R. Cardona. Monte Carlo study of a mixed spin-3/2and spin-1/2Ising ferrimagnetic model. Phy. Rev. B,1999,59(10):6784-6789.
[70]M. Jascur, J. Strecka. Magnetic properties of a mixed spin-1/2and spin-3/2Ising model with an uniaxial and biaxial crystal-field potential. Physica A,2005,358(3):393-412.
[71]J. Li, G. Z. Wei, A. Du. Compensation phenomena of a mixed spin-2and spin-1/2Heisenberg ferrimagnetic model:Green function study. Physica B,2005,368(4):121-130.
[72]D. Bayram, K. Mustafa, C. Osman. Magnetic properties of an anti-ferromagnetic and ferrimagnetic mixed spin-1/2and spin-5/2Ising model in the longitudinal magnetic field within the effective-field approximation. Physica A,2009,388(9):1835-1848.
[73]G. Z. Wei, Q. Zhang, Y. W. Gu. Monte Carlo studies of critical phenomena in mixed spin-1and spin-3/2Blume-Capel Ising model on simple cubic lattice. J. Magn. Magn. Mater.,2006,301(6):245-250.
[74]W. Jiang, G. Z. Wei, Z. D. Zhang. Tricritical behavior and magnetic properties for a mixed spin-1and spin-3/2transverse Ising model with a crystal field. Phys. Rev. B,2003,68:134432-124439.
[75]G. Z. Wei, Y. W. Gu, J. Liu. Mean-field and Monte Carlo studies of a mixed spin-1and spin-2Ising system with different anisotropies, Phys. Rev. B,2006,74(2):024422-1-024422-5.
[76]D. Bayram, E. Mehmet, K. Mustafa. The effective-field theory studies of critical phenomena in a mixed spin-1and spin-2Ising model on honeycomb and square lattices. Physica A,2010,389(10):2036-2047.
[77]D. Bayram, M. Bati, K. Mustafa. The effective-field study of a mixed spin-1and spin-5/2Ising ferrimagnetic system. Physica Scripta,2009,79(6):065006-065011.
[78]K. Mustafa, O. Canko, M. Bati. Dynamic phase diagrams of a mixed spin-1and spin-5/2Ising system in an oscillating magnetic field. Journal of the Korean Physical Society,2009,55(4):1344-1356.
[79]E. Albayrak. The critical and compensation temperatures for the mixed spin-3/2and spin-2Ising model. Physica B,2007,391(2):47-53.
[80]K. Mustafa, P. Yasin. Phase diagrams of an one equilibrium mixed spin-3/2and spin-2Ising system in an oscillating magnetic field. J. Magn. Magn. Mater.,2009,321(23):3905-3912.
[81]E. Albayrak, A. Yigit. Mixed spin-3/2and spin-5/2Ising system on the Bethe lattice. Phys. Lett. A,2006,353(2-3):121-129.
[82]K. Hadey Mohamad. Spin compensation temperatures induced by longitudinal fields in a mixed spin-3/2and spin-5/2Ising ferrimagnet. J. Magn. Magn. Mater.,2011,323(7):61-65.
[83]缪海凌,魏国柱.混自旋σ=3/2和S=2与σ=3/2和S=5/2Ising系统基态性质的比较.东北大学学报,2008,29(7):1057-1060.
[84]D. Bayram, K. Mustafa, C. Osman. Kinetics of a mixed spin-1/2and spin-3/2Ising ferromagnetic model. J. Magn. Magn. Mater.,2009,321(5):458-466.
[85]T. Kaneyoshi, Y. Nakamura, S. Shin. A diluted mixed spin-2and spin-5/2ferrimagnetic Ising system:a study of a molecular-based magnet. J. Phys.:Condens. Matt.,1998,(10):7025-7035.
[86]Q. Zhang, G. Z. Wei. Compensation temperatures of mixed spin-2and spin-5/2ferrimagnetic system with interlayer coupling:a study of a molecular-based magnet. J. Magn. Magn. Mater.,2002,253(3):96-104.
[87]G. Z. Wei, Q. Zhang, Z. H. Xin, Y. Q. Liang. Internal energy and initial susceptibility of mixed spin-2and spin-5/2ferrimagnetic Ising system with interlayer coupling. J. Magn. Magn. Mater.,2004,277(1-2):1-15.
[88]G. Z Wei, Q. Zhang, J. Zhao, Y. W. Gu. Tricritical behavior of mixed spin-2and spin-5/2ferrimagnetic Ising system with interlayer coupling. Physica B,2006,381(1-2):6-11.
[89]K. L. Yao, J. W. Li, Z. L. Liu, H. H. Fu, L. Zu. Magnetic Properties of a mixed spin-2and spin-5/2Heisenberg ferrimagnetic system on a two-dimensional honeycomb lattice:Green's function approach. Commun. Theor. Phys.,2007,47(4):741-745.
[90]A. Yigit, E. Albayrak. A bethe lattice study of the mixed spin-2and spin-5/2Ising model. J. Magn. Magn. Mater.,2007,309(1):87-95.
[91]E. Albayrak. Mixed spin-2and spin-5/2Blume-Emery-Griffiths model. Physica A,2007,375(10):174-184.
[92]K. Hadey Mohamad, E. P. Domashevskaya, A. F. Klinskikh. Spin compensation temperatures in the mean-field approximation of a mixed spin-2and spin-5/2Ising ferrimagnetic system. Physica A,2009,388(22):4713-4718.
[93]J. Li, A. Du, G. Z. Wei. Green function study of a mixed spin-2and spin-5/2Heisenberg ferrimagnetic system on a honeycomb lattice, phys. stat. sol.(b),2003,238(1):191-197.
[94]J. Li, A. Du, G. Z. Wei. The Compensation Behavior of mixed spin-2and spin-1/2Heisenberg ferrimagnetic system on a honeycomb lattice. Physica B,2004,348:79-88.
[95]J. Li, A. Du, G. Z. Wei. The compensation behavior and initial susceptibilities of a mixed-spin Heisenberg ferrimagnetic system in an external magnetic field. International Journal of Modern Physica B,2007,21(7):1077-1087.
[96]M. H. L. Pryce. The Theory of Magnetic resonance-line widths in crystals. Phys. Soc. A,1950,63(1):25-41.
[97]A. Abragam and M. H. L. Pryce. Theory of the nuclear hyperfine structure of paramagnetic resonance spectra in crystals. Phys. Soc. A,1951,205(1):135-148.
[98]J. Stephenson. Ising model with antiferromagnetic next-nearest-neighbor coupling:by mean-field model and disorder points. Phys. Rev. B,1977,15(11):5453-5461.
[99]C. S. O. Yokoi, M. D. Coutinho-Filho, S. R. Salinas. Ising model with competing axial interactions in the presence of a field:A mean-field treatment. Phys. Rev. B,1985,24(7):4047-4061.
[100]K. Walasek, K. Lukierska-Walasek. Quantum transverse Ising spin-glass model in the mean-field approximation. Phy. Rev. B,1986,34(7):4962-4965.
[101] W. M. Ng, J. H. Barry. Cluster-variation method applied in the pair approximation to the S=1Ising ferromagnet having additional single-ion-type uniaxial anisotropy. Phys. Rev. B,1978,17(9):3675~3683.
[102] T. Yokota. Random-field Ising model in the pair approximation. Phys. Rev. B,1988,38(16):11669~11672.
[103] Y. Ma, Z. Li. Pair-approximation method for the quantum transverse Ising model with a randomfield.P8hys. Rev. B,1990,41(16):11392~11395.
[104] M. N. Tamashiro, S. R. Salinas. Bethe-Peierls approximation for the triangular Isingantiferromagnet in a field.P8H6hys. Rev. B,1997,56(13):8241~8247.
[105] S. Krinsky. Bethe approximation to the magnetization is upper bound for Ising ferromagnet. Phys.Rev. B,1975,11(5):1970~1975.
[106] R. G. Priest. Exact renormalization-group equations in one dimension: the Ising model. Phys. Rev.B,1975,11(9):3461~3462.
[107] C. Unger. Renormalization-group study of the ferromagnetic Ising-model on the triangular lattice.Phys. Rev. B,1984,30(3):1511~1522.
[108] N. Metropolis, A. W. Rosenbluth, M. N. Rosenbluth, A. H. Teller, E. Teller. Equation of statecalculations by fast computing machines. J. Chem. Phys.,1953,21:1087~1095.
[109]李容.基于Monte Carlo模拟的Ca3Co2O6低温磁性研究:(硕士学位论文).兰州:兰州大学,2009.
[110] J. Christopher. Nuttall, D. Peter. Magnetization of the layer compounds AFeIIFeIII(C2O4)3(A=organic cation), in low and high magnetic fields: manifestation of Néel N and Q typeferrimagnetism in a Molecular Lattice.Chem. Mater.,1998,10(10):3050~3057.
[111] C. B. Peng, Y. Cao, D. S. Dai. Magnetic properties of Ag/Ni multilayered films. J. Appl. Phys.,1992,71(7):3457~3461.
[112]冯倩,黄志高,都有为.磁性多层膜磁特性的表面效应.物理学报,2003,52(11):2906~2910.
[113]黄志高.纳米结构材料磁特性的数值模拟:(博士学位论文).南京:南京大学,2004.
[114] A. Zaim, Y. EL Amraoui, M. Kerouad, H. Arhchoui. Monte Carlo study of the spin-1Blume–Capel Ising film. J. Magn. Magn. Mater,2008,320(6):1030~1037.
[115] G. D. Tang, Y. He, F. Liang, S. Li, Y. Huang. Multiple magnetic-pole reversals in themolecular-based mixed-valency ferrimagnet {[N(n-CII4H9)4][FeFeIII(C2O4)3]}n. Physica B,2007,392(3):337~340.
[116] C. Mathoniere, S. G. Carling, D. Yusheng, P. Day. Molecular-based mixed valencyferrimagnets (XRIII4)FeIIFe(C2O4)3(X=N, P; R=n-propyl, n-butyl, phenyl): anomalous negativemagnetisation in the tetra-n-butylammonium derivative. Chem. Soc. Chem. Commun.1994,(13):1551~1552.
[117] D. Ian, Watts, G. Simon, Carling, D. Peter. Synthesis, structure and magnetic properties oforganic-intercalated bimetallic molecular-based ferrimagnets (n-CnH2n+1)PPh3MIIFeIII(C2O4)3,(MII=Mn, Fe; n=3–7). J. Chem. Soc., Dalton Trans.,2002,7(1):1429-1434.
[118] R. S. Fishman, F. A. Reboredo. Magnetic anisotropy in the Fe(II)Fe(III) bimetallic oxalates. Phys.Rev. B,2008,77(14):144421~144430.
[119]李军,侯予,林韶宁,陈纯正.小型低温透平制冷机中电动机和发电机的应用.低温与超导,2005,33(1):14~16.
[120] E. E. Vogel, J. Cartes, P. Vargas, D. Altbir, S. Kobe, T. Kloze, M. Nogala. Hysteresis in±JIsing square lattices. Phys. Rev. B,1999,59(5):3325~3328.
[121] M. Oshikawa, M. Yamanaka, I. Affeck. Magnetization plateaus in spin chains:“Haldane Gap”for half-integer spins. Phys. Rev. Lett.,1997,78(10):1984~1987.
[122] C. Ekiz, H. Yaraneri. The magnetization plateaus of general Ising system with single-ionanisotropy. J. Magn. Magn. Mater.,2007,318(1-2):49~57.
[123] E. S. Carrillo, R. Franco, J. S. Valencia. Magnetic properties of a ferrimagnetic mixed (1,3/2)spin chain with inhomogeneous crystal field anisotropy. J. Magn. Magn. Mater.,2010,322(9H514):1917~1922.
[124] J. Wang, Y. Liu, Z. Xie, Q. M. Ma. The step effect of hysteresis loop in FM/AFM magneticsystem. Journal of Physics: Conference Series,2006,29(29):65~68.
[125] W. Jiang, L. M. Liu, X. X. Li, Q. Deng, H.Y. Guan, F. Zhang, A. B. Guo.Magnetization plateausof a ferrimagnetic nanoparticle in the presence of single-ion anisotropies. Physica B,2012,407(19):3933~3938.
[126] J. Kushauer, R. Van Bentum, W. Kleemann, D. Bertrand. Athermal magnetization avalanches anddomain states in the site-diluted metamagnet FexMg1-xCl2. Phys. Rev. B,1996,53(17):11647~11655.
[127] J. H. Zhang, F. Chen, J. Li, Charles J. O. Connor. Magnetic property of layeredcompound NbFeTe2. J. Appl. Phys.,1997,81(8):5283~5285.
[128] G. Alejandro, L. B. Steren, A. Caneiro, J. Cartes, E. E. Vogel, P. Vargas. Barkhausen-like stepsand magnetic frustration in doped La0.67xAxCa0.33MnO3(A=Ce,Y). Phys. Rev. B,2006,73(1):054427~054434.