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arXiv 2008.07735cond-mat.mtrl-sci
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$_x$ Fe $_{1-x}$金属玻璃交换耦合常数的第一性原理研究

First-principles study of exchange coupling constants in Nd$_x$Fe$_{1-x}$ amorphous alloy

Asako Terasawa, Yoshihiro Gohda

摘要:

采用第一性原理计算研究了不同成分的$_x$-Fe $_{1-x}$非晶合金的交换耦合常数$J_{ij}$.我们观察到$J_{ij}$的原子依赖性及其涨落。我们发现,组合物强烈影响的距离依赖性的$J_{ij}$。对于$x<0.5$,计算的居里温度的组成依赖性是适度的。为了考察局部环境对交换耦合的影响,我们使用Gabriel图演示了配位结构和交换耦合常数的联合分析。研究表明,居里温度主要受平均$J_{ij}$和由相邻原子对决定的配位数的影响。我们还观察到,随着Nd原子数的增加,Fe-Fe和Fe-Nd之间的交换耦合增强。

英文摘要:

We investigate the exchange coupling constant $J_{ij}$ in Nd$_x$Fe$_{1-x}$ amorphous alloys with different compositions within the framework of first-principles calculation. We observed a strong atomic-dependence of $J_{ij}$ and its fluctuations. We show that the composition strongly affects the distance dependence of $J_{ij}$. Composition dependence of calculated Curie temperatures is modest for $x<0.5$. To examine the effect of the local environment on the exchange couplings, we demonstrate combined analyses of the coordination structure and exchange coupling constants using the Gabriel graph. Our study reveals that the Curie temperatures are mostly dominated by the averaged $J_{ij}$ and coordination numbers determined by the pairs of neighboring atoms. We also observed that the exchange couplings between Fe--Fe and Fe--Nd become stronger with increasing the number of surrounding Nd atoms.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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