Critical role of interface states for spin-dependent tunneling in half-metallic Co2MnSi-based magnetic tunnel junctions investigated by tunneling spectroscopy

Ishikawa, Takayuki; Itabashi, Naoki; Taira, Tomoyuki; Matsuda, Ken-ichi; Uemura, Tetsuya; Yamamoto, Masafumi
March 2009
Applied Physics Letters;3/2/2009, Vol. 94 Issue 9, pN.PAG
Academic Journal
We investigated at 4.2 K the differential conductance (dI/dV) versus V characteristics of fully epitaxial Co2MnSi/MgO/Co2MnSi magnetic tunnel junctions (MTJs) featuring high tunnel magnetoresistance ratios of about 700% at 4.2 K (about 180% at room temperature). We developed a tunneling model to explain the observed tunneling spectra and showed the critical role played by interface states for minority spins existing around the Fermi level of Co2MnSi electrodes facing a MgO tunnel barrier in the spin-dependent tunneling characteristics of these MTJs with half-metallic electrodes.


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