Enhanced tunnel magnetoresistance in a spinel oxide barrier with cation-site disorder

Hiroaki Sukegawa; Yoshio Miura; Shingo Muramoto; Seiji Mitani; Tomohiko Niizeki; Tadakatsu Ohkubo; Kazutaka Abe; Masafumi Shirai; Koichiro Inomata; Kazuhiro Hono

doi:10.1103/PhysRevB.86.184401

Enhanced tunnel magnetoresistance in a spinel oxide barrier with cation-site disorder

Hiroaki Sukegawa, Yoshio Miura, Shingo Muramoto, Seiji Mitani, Tomohiko Niizeki, Tadakatsu Ohkubo, Kazutaka Abe, Masafumi Shirai, Koichiro Inomata, Kazuhiro Hono

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Abstract

We report enhanced tunnel magnetoresistance (TMR) ratios of 188% (308%) at room temperature and 328% (479%) at 15 K for cation-site-disordered MgAl ₂O ₄-barrier magnetic tunnel junctions (MTJs) with Fe (Fe _0.5Co _0.5 alloy) electrodes, which exceed the TMR ratios theoretically calculated and experimentally observed for ordered spinel barriers. The enhancement of TMR ratios is attributed to the suppression of the so-called band-folding effect in ordered spinel MTJs. First-principles calculations describe a dominant role of the oxygen sublattice for spin-dependent coherent tunneling, suggesting a mechanism of coherent tunneling occurring even in the disordered systems.

Original language	English
Article number	184401
Journal	Physical Review B - Condensed Matter and Materials Physics
Volume	86
Issue number	18
DOIs	https://doi.org/10.1103/PhysRevB.86.184401
Publication status	Published - 2012 Nov 2

ASJC Scopus subject areas

Electronic, Optical and Magnetic Materials
Condensed Matter Physics

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abstract = "We report enhanced tunnel magnetoresistance (TMR) ratios of 188% (308%) at room temperature and 328% (479%) at 15 K for cation-site-disordered MgAl 2O 4-barrier magnetic tunnel junctions (MTJs) with Fe (Fe 0.5Co 0.5 alloy) electrodes, which exceed the TMR ratios theoretically calculated and experimentally observed for ordered spinel barriers. The enhancement of TMR ratios is attributed to the suppression of the so-called band-folding effect in ordered spinel MTJs. First-principles calculations describe a dominant role of the oxygen sublattice for spin-dependent coherent tunneling, suggesting a mechanism of coherent tunneling occurring even in the disordered systems.",

author = "Hiroaki Sukegawa and Yoshio Miura and Shingo Muramoto and Seiji Mitani and Tomohiko Niizeki and Tadakatsu Ohkubo and Kazutaka Abe and Masafumi Shirai and Koichiro Inomata and Kazuhiro Hono",

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T1 - Enhanced tunnel magnetoresistance in a spinel oxide barrier with cation-site disorder

AU - Sukegawa, Hiroaki

AU - Miura, Yoshio

AU - Muramoto, Shingo

AU - Mitani, Seiji

AU - Niizeki, Tomohiko

AU - Ohkubo, Tadakatsu

AU - Abe, Kazutaka

AU - Shirai, Masafumi

AU - Inomata, Koichiro

AU - Hono, Kazuhiro

PY - 2012/11/2

Y1 - 2012/11/2

N2 - We report enhanced tunnel magnetoresistance (TMR) ratios of 188% (308%) at room temperature and 328% (479%) at 15 K for cation-site-disordered MgAl 2O 4-barrier magnetic tunnel junctions (MTJs) with Fe (Fe 0.5Co 0.5 alloy) electrodes, which exceed the TMR ratios theoretically calculated and experimentally observed for ordered spinel barriers. The enhancement of TMR ratios is attributed to the suppression of the so-called band-folding effect in ordered spinel MTJs. First-principles calculations describe a dominant role of the oxygen sublattice for spin-dependent coherent tunneling, suggesting a mechanism of coherent tunneling occurring even in the disordered systems.

AB - We report enhanced tunnel magnetoresistance (TMR) ratios of 188% (308%) at room temperature and 328% (479%) at 15 K for cation-site-disordered MgAl 2O 4-barrier magnetic tunnel junctions (MTJs) with Fe (Fe 0.5Co 0.5 alloy) electrodes, which exceed the TMR ratios theoretically calculated and experimentally observed for ordered spinel barriers. The enhancement of TMR ratios is attributed to the suppression of the so-called band-folding effect in ordered spinel MTJs. First-principles calculations describe a dominant role of the oxygen sublattice for spin-dependent coherent tunneling, suggesting a mechanism of coherent tunneling occurring even in the disordered systems.

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Enhanced tunnel magnetoresistance in a spinel oxide barrier with cation-site disorder

Abstract

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