Perpendicular magnetic anisotropy at the Fe/MgAl${}_2$O${}_4$ interface: Comparative first-principles study with Fe/MgO

Abstract

We present a theoretical study on interfacial magnetocrystalline anisotropy for Fe/MgAl${}_2$O${}_4$. This system has a very small lattice mismatch at the interface and therefore is suitable for realizing a fully coherent ferromagnet/oxide interface for magnetic tunnel junctions. On the basis of density functional theory, we calculate the interfacial anisotropy constant $K_{\mathrm{i}}$ and show that this system has interfacial perpendicular magnetic anisotropy (PMA) with $K_{\mathrm{i}}\approx 1.2mJ/{\mathrm{m}}^2$, which is a little bit smaller than that of Fe/MgO ($K_{\mathrm{i}}\approx$ 1.5--1.7$mJ/{\mathrm{m}}^2$). Second-order perturbation analysis with respect to the spin-orbit interaction clarifies that the difference in $K_{\mathrm{i}}$ between Fe/MgAl${}_2$O${}_4$ and Fe/MgO originates from the difference in contributions from spin-flip scattering terms at the interface. We propose that the insertion of tungsten layers into the interface of Fe/MgAl${}_2$O${}_4$ is a promising way to obtain huge interfacial PMA with $K_{\mathrm{i}}\gtrsim 3mJ/{\mathrm{m}}^2$.

24 pages, 10 figures, 1 table

References in corpus (3)

• Large perpendicular magnetic anisotropy in epitaxial Fe/MgAl2O4(001) heterostructures
• Bias voltage effects on tunneling magnetoresistance in Fe/MgAl${}_2$O${}_4$/Fe(001) junctions: Comparative study with Fe/MgO/Fe(001) junctions
• Giant interfacial perpendicular magnetic anisotropy in Fe/CuIn${}_{1-x}$Ga${}_x$Se${}_2$ beyond Fe/MgO

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• Magnetic anisotropy of ferromagnetic metals in low-symmetry systems
• The origin of enhanced interfacial perpendicular magnetic anisotropy in LiF-inserted Fe/MgO interface
• First-principles study of enhancement of perpendicular magnetic anisotropy obtained by inserting an ultrathin LiF layer at an Fe/MgO interface