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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76 Citations (Scopus)


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 languageEnglish
Article number184401
JournalPhysical Review B - Condensed Matter and Materials Physics
Issue number18
Publication statusPublished - 2012 Nov 2


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