Exchange interaction in L10-ordered FePt and CoPt from first-principles
Exchange interaction in L10-ordered FePt and CoPt from first-principles
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DOI：
10.1063/1.3564953
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发表时间：
2011-04
影响因子：
3.2
通讯作者：
X. B. Liu;Z. Altounian
中科院分区：
文献类型：
--
作者：
X. B. Liu;Z. Altounian
用第一性原理密度泛函方法研究了具有四元L10型结构的FePt和CoPt的交换作用。对于FePt，Fe在1a和1c位的有效交换参数JFe 1a和JFe 1c具有相同的负值（-1.40 mRy），而Fe（1a）和Fe（1c）之间的有效交换参数JFe 1a-1c具有较大的正值（8.29 mRy），而JFe-Pt也具有正值（1.20 mRy）。类似地，对于CoPt，交换参数为JCo 1a = JCo 1c = −0.86 mRy，JCo 1a-1c = 8.47 mRy和JCo-Pt = 1.30 mRy。FePt和CoPt的平均场TC分别为802 K和870 K，与实验结果吻合较好。在FePt和CoPt中，TC分别在c/a = 1处显示峰值，这是由负交换相互作用和正交换相互作用的相互作用引起的。
The exchange interactions have been studied from a first-principles density functional calculation in FePt and CoPt with the tetragonal L10-type structure. For FePt, the effective exchange parameters of Fe at the sites 1a and 1c, JFe1a and JFe1c, have the same negative value (−1.40 mRy) while that between Fe (1a) and Fe (1c), JFe1a-1c, have a large positive value (8.29 mRy) and JFe-Pt also has a positive value (1.20 mRy). Similarly, for CoPt, the exchange parameters are JCo1a = JCo1c = −0.86 mRy, JCo1a-1c = 8.47 mRy and JCo-Pt = 1.30 mRy. The estimated mean fields TC are about 802 K and 870 K for FePt and CoPt, respectively, in good agreement with the experiments. TC shows peak value at c/a = 1 in FePt and CoPt, respectively, resulting from the interplay between negative and positive exchange interactions.