Mechanism of Uniaxial Magnetocrystalline Anisotropy in Transition Metal Alloys
Mechanism of Uniaxial Magnetocrystalline Anisotropy in Transition Metal Alloys
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DOI：
10.7566/jpsj.83.034715
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发表时间：
2014-03-01
影响因子：
1.7
通讯作者：
Sakuma, Akimasa
中科院分区：
文献类型：
--
作者：
Kota, Yohei;Sakuma, Akimasa
采用第一性原理计算方法研究了过渡金属合金（FePt，CoPt，FePd，MnAl，MnGa，FeCo）的磁晶各向异性，阐明了其特殊机理.在局域自旋密度近似下，采用紧束缚线性muffin-tin轨道方法计算了各化合物的电子结构，并根据磁力定理和自旋轨道相互作用的二级微扰理论计算了各向异性能.本文系统地描述了真实的材料中单轴磁晶各向异性的机理，提出了提高各向异性能的条件。FePt和CoPt中大的磁晶各向异性能来自Pt的强自旋-轨道相互作用。相反，即使MnAl，MnGa和FeCo中的自旋-轨道相互作用很弱，这些化合物的各向异性能与FePd的各向异性能相当。我们发现MnAl、MnGa和FeCo的电子结构能有效地诱导磁晶各向异性，这是自旋轨道相互作用的选择规则
Magnetocrystalline anisotropy in transition metal alloys (FePt, CoPt, FePd, MnAl, MnGa, and FeCo) was studied using first-principles calculations to elucidate its specific mechanism. The tight-binding linear muffin-tin orbital method in the local spin-density approximation was employed to calculate the electronic structure of each compound, and the anisotropy energy was evaluated using the magnetic force theorem and the second-order perturbation theory in terms of spin-orbit interactions. We systematically describe the mechanism of uniaxial magnetocrystalline anisotropy in real materials and present the conditions under which the anisotropy energy can be increased. The large agnetocrystalline anisotropy energy in FePt and CoPt arises from the strong spin-orbit interaction of Pt. In contrast, even though the spin-orbit interaction in MnAl, MnGa, and FeCo is weak, the anisotropy energies of these compounds are comparable to that of FePd. We found that MnAl, MnGa, and FeCo have an electronic structure that is efficient in inducing the magnetocrystalline anisotropy in terms of the selection rule of spin-orbit interaction