Particle size dependence of atomic ordering and magnetic properties of L10-FePd nanoparticles
Particle size dependence of atomic ordering and magnetic properties of L10-FePd nanoparticles
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DOI：
10.1016/j.jmmm.2006.11.104
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发表时间：
2007-03
影响因子：
2.7
通讯作者：
H. Naganuma;Kazuhisa Sato;Y. Hirotsu
中科院分区：
文献类型：
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作者：
H. Naganuma;Kazuhisa Sato;Y. Hirotsu
用电子束蒸发法制备了平均粒径在4~15 nm之间的L10型FEPD纳米粒子。与尺寸为10 nm的FEPD纳米颗粒相比，尺寸小于8 nm的FEPD纳米颗粒的矫顽力和剩磁都很低。矫顽力和剩磁都随着温度的降低而增加，表明在较低的温度下，磁矩的热激荡受到了很大的抑制。对于尺寸约为6 nm的FEPD纳米粒子，在零场冷(ZFC)和场冷(FC)磁化强度的温度依赖关系中出现了超顺磁性行为。由于L10-结构的长程有序(LRO)参数的降低以及磁矩的热搅拌，较小尺寸的FEPD纳米颗粒的硬磁性能的消失是归因于L10结构的长程有序(LRO)参数的降低和磁矩的热搅拌。
L10-type FePd nanoparticles with mean sizes between 4 and 15nm in diameter have been fabricated by electron beam evaporation. Coercivity and remanence of FePd nanoparticles with sizes less than about 8nm were quite low compared to the values for 10-nm-sized FePd nanoparticles. Both coercivity and remanence increased with decreasing the temperature, indicating the large suppression of the thermal agitation of the magnetic moment at lower temperatures. Superparamagnetic behavior appeared in zero-field-cooled (ZFC) and field-cooled (FC) temperature dependence of magnetization for about 6-nm-sized FePd nanoparticles. Disappearance of the hard magnetic properties in smaller sized FePd nanoparticles is attributed to the reduction of the long-range order (LRO) parameter of the L10-structure as well as the thermal agitation of magnetic moment.