铁铂纳米线的磁力显微术研究
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摘要
本研究利用磁力显微术扫描观测了附着在二氧化硅衬底上的铁铂纳米线样品的表面形貌和磁性结构,实现了对铁铂纳米线磁学信息的成像.将磁学信息成像中的明暗分布与纳米线的形貌成像相结合,分析了铁铂纳米线的磁极分布.磁极方向相反的纳米线聚集在一起的现象表明磁化材料总是趋于能量最低的状态.通过改变外加磁场的强度和方向控制铁铂纳米线内部的磁化状态,观测到磁极反转现象.
In this study, MFM is used to scan and observe the surface and magnetization of FePt nanowires scattered on a SiO_2 substrate and their magnetic images are also obtained. The magnetizaion distribution of FePt nanowires is analyzed based on bright and dark regions shown on magnetic images. The aggregation of nanowires with opposite magnetization indicates magnetic materials always tend to be in the lowest energy state. The orientation of magnetization of FePt nanowires can be controlled and magnetic reversal is observed by applying external magnetic field.
In this study, MFM is used to scan and observe the surface and magnetization of FePt nanowires scattered on a SiO_2 substrate and their magnetic images are also obtained. The magnetizaion distribution of FePt nanowires is analyzed based on bright and dark regions shown on magnetic images. The aggregation of nanowires with opposite magnetization indicates magnetic materials always tend to be in the lowest energy state. The orientation of magnetization of FePt nanowires can be controlled and magnetic reversal is observed by applying external magnetic field.
引文
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[2] R.加西亚.振幅调制原子力显微术[M].程志海,裘晓辉,译.北京:科学出版社,2016.
[3] 程敏熙,熊钰庆.STM的同胞兄弟——原子力显微镜(AFM)[J].大学物理,2000,19(9):38-42.
[4] 韩宝善.磁力显微镜的发展和应用[J].物理,1997,26(10):671-624.
[5] 程志海,郑志月,裘晓辉.原子力显微术研究进展[J].物理,2016,45(3):180-187.
[6] Sun SH,et al.Monodisperse FePt nanoparticles and ferromagnetic FePt nanocrystal superlattices [J].Science,2000,287 (5460):1989-1992.
[7] Elkins K,Li D,Poudyal N,et al.Monodisperse face-centred tetragonal FePt nanoparticles with giant coercivity [J].J Phys D:Appl phys,2005,38:2306-2309.
[8] Sun S.Recent Advances in Chemical Synthesis,Self-Assembly,and Applications of FePt Nanoparticles[J].Advanced Materials & Processes,2006,18(4):393-403.
[9] Skumryev V,Stoyanov S,Zhang Y,et al.Beating the superparamagnetic limit with exchange bias.Nature,2003,423:850-853.
[10] Weller D,Moser A.Thermal effect limits in ultra high density magnetic recording [J].IEEE Trans.Magn.,1999,35:4423-4439.
[11] Konagai T,Kitahara Y,Itoh T,et.al.Perpendicular anisotropy of MBE-grown FePt-Ag granular films [J].Journal of Magnetism and Magnetic Materials,2007,310(2):2662-2664.
[12] Laenens B,Almeida F M,Lanekaert N P,et al.Interplay between structural and magnetic properties of L10-FePt(001) thin films directly grown on MgO(001) [J].J Appl Phys,2009,105(7):073913.
[13] 莫小静,向晖,李国庆.垂直取向L10FePt纳米粒子的磁性[J].科学通报,2010,55(7):534-540.
[14] Lin J J,Zhang T,Lee P,et al.Magnetic trapping induced low temperature phase transition from fcc to fct in pulsed laster deposition of FePt:Al2O3 nanocomposite thin films [J].Appl Phys Lett,2007,91:063120.
[15] 向晖,莫小静,郑远平.耐高温垂直取向FePt连续薄膜的表明形貌与磁性[J].科学通报,2011,56(15):1188-1195.
[16] Nguyen V D,Vila L,Laczkowski P,et al.Detection of domain-wall position and magnetization reversal in nanostructures using the magnon contribution to the resistivity [J].Phys Rev Lett.2011,107,135605.
[17] Nguyen V D,Vila L,Marty A,et al.Dimensionality effects on the magnetization reversal in narrow FePt nanowires [J].Appl Phys Lett,2012,100:252403.
[18] Wang T,Wang Y,Fu Y,et al.A magnetic force microscopy study of the magnetic reversal of a single Fe nanowire[J].Nanotechnology,2009,20:105707.