Localized magnetic moments in the Heusler alloy Rh2MnGe
Localized magnetic moments in the Heusler alloy Rh2MnGe
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DOI：
10.1088/0022-3727/42/8/084001
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发表时间：
2009-04
期刊：
影响因子：
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通讯作者：
P. Klaer;M. Kallmayer;H. Elmers;L. Basit;J. Thöne;S. Chadov;C. Felser
中科院分区：
文献类型：
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作者：
P. Klaer;M. Kallmayer;H. Elmers;L. Basit;J. Thöne;S. Chadov;C. Felser
已在软 X 射线区域中测量了铁磁 Heusler 合金 Rh2MnGe 在 Rh M3,2 和 Mn L3,2 边缘处的核级吸收（X 射线吸收光谱，XAS）光谱的 X 射线磁圆二色性 (XMCD)。 Rh和Mn自旋矩之比为0.05，小于通过局域密度近似电子能带结构计算确定的0.1之比。我们发现Rh 4d 和Mn 3d 态的轨道矩非常小。观察到的 Rh 2p XAS 光谱可以根据金属典型的未占据状态的 Rh 3d 部分密度来理解。 Mn 2p XAS 和 XMCD 光谱的观察到的特征主要是终态多重态，这对于氧化物来说是典型的。实验和从头计算的 XAS/XMCD 光谱的比较揭示了 Mn 3d 谱带的强烈变窄，表明 Mn 矩的强烈局域化。与等电子化合物 Co2MnGe 相比，Rh2MnGe 的磁矩更加局部化。尽管 Mn 矩具有很强的局域性，但与海森堡模型的预测相反，Mn 和 Rh 亚晶格的亚晶格磁化强度的温度依赖性是相同的。这可能归因于 Rh 时刻剩余的流动特征。
X-ray magnetic circular dichroism (XMCD) of core-level absorption (x-ray absorption spectroscopy, XAS) spectra in the soft x-ray region has been measured for the ferromagnetic Heusler alloy Rh2MnGe at the Rh M3,2 and Mn L3,2 edges. The ratio of Rh and Mn spin moments amounts to 0.05 which is smaller than the ratio of 0.1 determined by a local density approximation electronic band structure calculation. We have found that the orbital moments of the Rh 4d and Mn 3d states are very small. The observed Rh 2p XAS spectrum can be understood on the basis of the Rh 3d partial density of unoccupied states as is typical for metals. The observed features of the Mn 2p XAS and XMCD spectra are dominated by final state multiplets as is typical for oxides. The comparison of experimental and ab initio calculated XAS/XMCD spectra reveals a strong narrowing of the Mn 3d bands, indicating strongly localized Mn moments. The magnetic moments are considerably more localized for Rh2MnGe in comparison with the isoelectronic compound Co2MnGe. In spite of the strong localization of the Mn moment, the temperature dependences of sublattice magnetization are equal for the Mn and Rh sublattices in contrast to the prediction by a Heisenberg model. This might be attributed to the remaining itinerant character of the Rh moment.