Interfacial giant tunnel magnetoresistance and bulk-induced large perpendicular magnetic anisotropy in (111)-oriented junctions with fcc ferromagnetic alloys: A first-principles study
| Autor: | Yoshiaki Sonobe, Hiroyoshi Itoh, Seiji Mitani, Yoshio Miura, Hiroaki Sukegawa, Keisuke Masuda |
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| Rok vydání: | 2021 |
| Předmět: |
Condensed Matter - Materials Science
Materials science Condensed matter physics Anisotropy energy Fermi level Materials Science (cond-mat.mtrl-sci) FOS: Physical sciences 02 engineering and technology Condensed Matter::Mesoscopic Systems and Quantum Hall Effect 021001 nanoscience & nanotechnology Antibonding molecular orbital Magnetocrystalline anisotropy 01 natural sciences Condensed Matter::Materials Science symbols.namesake Tunnel magnetoresistance Ferromagnetism 0103 physical sciences symbols 010306 general physics 0210 nano-technology Anisotropy Quantum tunnelling |
| Zdroj: | Physical Review B. 103 |
| ISSN: | 2469-9969 2469-9950 |
| DOI: | 10.1103/physrevb.103.064427 |
| Popis: | We study the tunnel magnetoresistance (TMR) effect and magnetocrystalline anisotropy in a series of magnetic tunnel junctions (MTJs) with $L1_1$-ordered fcc ferromagnetic alloys and MgO barrier along the [111] direction. Considering the (111)-oriented MTJs with different $L1_1$ alloys, we calculate their TMR ratios and magnetocrystalline anisotropies on the basis of the first-principles calculations. The analysis shows that the MTJs with Co-based alloys (CoNi, CoPt, and CoPd) have high TMR ratios over 2000$\%$. These MTJs have energetically favored Co-O interfaces where interfacial antibonding between Co $d$ and O $p$ states is formed around the Fermi level. We find that the resonant tunneling of the antibonding states, called the interface resonant tunneling, is the origin of the obtained high TMR ratios. Our calculation of the magnetocrystalline anisotropy shows that many $L1_1$ alloys have large perpendicular magnetic anisotropy (PMA). In particular, CoPt has the largest value of anisotropy energy $K_{\rm u} \approx 10\,{\rm MJ/m^3}$. We further conduct a perturbation analysis of the PMA with respect to the spin-orbit interaction and reveal that the large PMA in CoPt and CoNi mainly originates from spin-conserving perturbation processes around the Fermi level. Comment: 11 pages, 9 figures, 2 tables |
| Databáze: | OpenAIRE |
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