| Gigantic perpendicular magnetic anisotropy of heavy transition metal cappings on Fe/MgO(001) | |||||
| 작성자 | 김** | 작성일 | 2018-08-30 | 조회수 | 100 |
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Journal Article published Nov 2017 in Journal of Magnetism and Magnetic Materials volume 442 on pages 183 to 188
Authors: P. Taivansaikhan, D. Odkhuu, S.H. Rhim, S.C. Hong https://doi.org/10.1016/j.jmmm.2017.06.110 Abstract Effects of capping layer by 5d transition metals (TM = Hf, Ta, W, Re, Os, Ir, Pt, and Au) on Fe/MgO(0 0 1), a typical magnetic tunneling junction, are systematically investigated using first-principles calculation for magnetism and magnetocrystalline-anisotropy (MCA). The early TMs having less than half-filled d bands favor magnetization antiparallel to Fe, whereas the late TMs having more than half-filled d bands favor parallel, which is explained in the framework of kinetic exchange energy. The Os capping, isovalent to Fe, enhances MCA significantly to gigantic energy of +11.31 meV/cell, where positive contribution is mostly from the partially filled majority d bands of magnetic quantum number of |m| = 1 along with stronger spin-orbit coupling of Os than Fe. Different TM cappings give different MCA energies as the Fermi level shifts according to the valence of TM: Re and Ir, just one valence more or less than Os, have still large PMCA but smaller than the Os. In the W and Pt cappings, valence difference by two, PMCA are further reduced; MCAs are lowered compared to Fe/MgO(0 0 1) by the cappings of the very early TMs (Hf and Ta), while the very late TM (Au) switches sign to in-plane MCA. |
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