Orbital magnetic moment and coercivity of SiO2-coated FePt nanoparticles studied by x-ray magnetic circular dichroism
Orbital magnetic moment and coercivity of SiO2-coated FePt nanoparticles studied by x-ray magnetic circular dichroism
复制标题
X射线磁圆二色性研究SiO2包覆FePt纳米粒子的轨道磁矩和矫顽力
DOI：
10.1103/physrevb.90.024423
复制
发表时间：
2014
影响因子：
3.7
通讯作者：
and M. Takano
中科院分区：
文献类型：
--
作者：
Y. Takahashi;T. Kadono;V. R. Singh;V. K. Verma;K. Ishigami;G. Shibata;T. Harano;A. Fujimori;Y. Takeda;T. Okane;Y. Saito;H. Yamagami;S. Yamamoto;and M. Takano
我们通过 X 射线吸收光谱 (XAS) 和 X 射线磁圆二色性 (XMCD) 测量 Fe 吸收边缘，研究了 FePt 纳米颗粒中 Fe 的自旋和轨道磁矩。使用 XMCD 求和规则，我们评估了 Fe 的轨道磁矩 () 与有效自旋磁矩 () 的比率。该值与通过气相缩合制备的FePt纳米颗粒获得的值(0.09)相当，并且大于FePt薄膜获得的值(0.05)，表明高度的1有序。磁化强度的 FePt 分量的磁滞行为通过 XMCD 测量。室温下磁矫顽力()高达1.8 T，比薄膜值大3倍，比气相凝聚纳米颗粒大50倍。对于分布在 1 到 5 T 之间的非相互作用单域纳米粒子，Stoner-Wohlfarth 模型可以很好地解释滞后曲线。
We have investigated the spin and orbital magnetic moments of Fe in FePt nanoparticles in the1-ordered phase coated withby x-ray absorption spectroscopy (XAS) and x-ray magnetic circular dichroism (XMCD) measurements at the Feabsorption edges. Using XMCD sum rules, we evaluated the ratio of the orbital magnetic moment () to the effective spin magnetic moment () of Fe to be. Thisvalue is comparable to the value (0.09) obtained for FePt nanoparticles prepared by gas phase condensation, and is larger than the values (0.05) obtained for FePt thin films, indicating a high degree of1order. The hysteretic behavior of the FePt component of the magnetization was measured by XMCD. The magnetic coercivity () was found to be as large as 1.8 T at room temperature,3 times larger than the thin film value and50 times larger than that of the gas phase condensed nanoparticles. The hysteresis curve is well explained by the Stoner-Wohlfarth model for noninteracting single-domain nanoparticles with thedistributed from 1 to 5 T.