Size-dependent spin-reorientation transition in Nd2Fe14B nanoparticles
Size-dependent spin-reorientation transition in Nd2Fe14B nanoparticles
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DOI：
10.1016/j.physleta.2010.07.061
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发表时间：
2010-05
影响因子：
2.6
通讯作者：
C. Rong;N. Poudyal;J. Liu
中科院分区：
文献类型：
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作者：
C. Rong;N. Poudyal;J. Liu
众所周知，某些铁磁性质，如居里温度，是尺寸相关的。在这封信中，我们将报道，Nd{sub2}Fe{sub14}B材料的自旋重取向温度也与尺寸有关。采用表面活性剂辅助球磨技术，成功地制备了6、20和300 nm不同尺寸的Nd2Fe14B纳米粒子。通过测量直流磁化率和交流磁化率随温度的变化，确定了NdFeB纳米粒子的自旋重取向转变温度。结果表明，纳米粒子的自旋-重取向转变温度(T{subsr})强烈地依赖于尺寸。300 nm颗粒的T{subsr}低于大块原料，而20 nm颗粒的T{subsr}明显低于300 nm颗粒。讨论了这种大小依赖关系背后的物理机制。
It is well known that some ferromagnetic properties like Curie temperature are size dependent. In this Letter we will report that the spin-reorientation temperature of Nd{sub 2}Fe{sub 14}B material is also size dependent. By using a surfactant-assisted ball milling technique, Nd{sub 2}Fe{sub 14}B nanoparticles with different size about 6, 20 and 300 nm were successfully obtained. Spin-reorientation transition temperature of the NdFeB nanoparticles was then determined by measuring the temperature dependence of DC and AC magnetic susceptibility. It was revealed that the spin-reorientation transition temperature (T{sub sr}) of the nanoparticles is strongly size dependent. T{sub sr} of the 300 nm particles is lower than that of the bulk raw material while the T{sub sr} of the 20 nm particles is significantly lower than that for the 300 nm particles. The physics behind this size dependence is discussed.