Inverse tunnel magnetoresistance of magnetic tunnel junctions with a NiCo2O4 electrode
Source abstract
Abstract
Inverse spinel oxide NiCo2O4 (NCO) is known to exhibit ferrimagnetic characteristics and electrical conductivity. First-principles calculations predict NCO to be a half-metal with a negative polarization of −100%. In this study, we fabricated epitaxial NCO/MgO/Fe magnetic tunnel junctions by reactive molecular beam epitaxy and observed an inverse tunnel magnetoresistance (TMR) effect of −19.1% at 14 K, indicating that NCO has negative spin polarization. The TMR ratio monotonically decreased with increasing temperature, which was attributed to the temperature dependence of the NCO surface magnetization due to the thermal excitation of spin waves. In addition, the TMR ratio displayed strong bias voltage dependence, decreasing to less than half of the maximum value at +20 and −30 mV. These findings support the use of NCO in spintronic devices and should lead to further developments in oxide spintronics.
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Research context
OpenAlex topics: Magnetic properties of thin films · ZnO doping and properties · Semiconductor materials and devices
SciVX discovery tags are terminology-based. OpenAlex topics are source-provided classifications.
Affiliations
Graduate School of Chemical Science and Engineering, Hokkaido University 1 , Kita-13 Nishi-8, Sapporo, Hokkaido 060-8628, Japan
Graduate School of Engineering, Hokkaido University 2 , Kita-13 Nishi-8, Sapporo, Hokkaido 060-8628, Japan
Funding
Japan Society for the Promotion of Science · Institute for Chemical Research, Kyoto University · MEXT
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