Magnetization distribution in Cu0.6Mn2.4Ge2 ferromagnet from polarized and non-polarized neutron powder diffraction aided by density-functional theory calculations
Magnetization distribution in Cu0.6Mn2.4Ge2 ferromagnet from polarized and non-polarized neutron powder diffraction aided by density-functional theory calculations
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DOI：
10.1016/j.jmmm.2021.167827
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发表时间：
2021-03
影响因子：
2.7
通讯作者：
Zachary P. Tener;V. Yannello;Jenifer Willis;V. Ovidiu Garlea;M. Shatruk
中科院分区：
文献类型：
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作者：
Zachary P. Tener;V. Yannello;Jenifer Willis;V. Ovidiu Garlea;M. Shatruk
通过大量的磁性测量和中子散射实验，结合电子结构计算，重新研究了Cu_（0.6）Mn_（2.4）Ge_2的晶体结构和磁性.该材料为软铁磁体，有序温度TC = 316 K。在最大外加磁场为2 T和5 T时，由磁场相关磁化等温线估算的磁热效应分别为1.2J/（kg·K）和2.5J/（kg·K）。该化合物属于六方晶系P63/mmc空间群。一个复杂的结构障碍，需要测试几个障碍模型对非极化和极化中子散射实验和磁化测量的结果。还进行了密度泛函理论水平的模拟，以确定最稳健的解决方案，正确地描述了观察到的数据。最终的磁结构模型揭示了Mn 1和Mn 2原子上的不相等磁矩（分别为2.29（9）µ B和2.7（1）µB），以及在两个Mn位置中存在空位和轻微的Cu替代缺陷。这项工作演示了如何将非极化和极化中子散射方法与电子结构计算相结合，以建立具有复杂晶体学无序的磁性材料的微观结构。
The crystal structure and magnetic properties of Cu0.6Mn2.4Ge2have been re-investigated by a combination of extensive magnetic measurements and neutron scattering experiments, aided by electronic structure calculations. The material is found to be a soft ferromagnet with the ordering temperatureTC= 316 K. The magnetocaloric effect evaluated from field-dependent magnetization isotherms is equal to 1.2 J/(kg·K) and 2.5 J/(kg·K) under the maximum applied magnetic field of 2 T and 5 T, respectively. The compound crystallizes in the hexagonal space groupP63/mmc. A complex structural disorder necessitated testing of several disorder models against the results of non-polarized and polarized neutron scattering experiments and magnetization measurements. Simulations at the density-functional theory level were also performed to identify the most robust solution that properly described the data observed. The final magnetic structure model reveals non-equal magnetic moments on the Mn1 and Mn2 atoms (2.29(9) µBand 2.7(1) µB, respectively) and the presence of vacancies and minor Cu substitution defects in both Mn sites. The work demonstrates how the non-polarized and polarized neutron scattering methods can be combined with electronic structure calculations to establish the microscopic structure of magnetic materials with complex crystallographic disorder.