Volume 124, Number 4, November 2018
|Number of page(s)||5|
|Section||Condensed Matter: Structural, Mechanical and Thermal Properties|
|Published online||10 December 2018|
Structure and transport properties of amorphous high-κ Al2O3
1 Center for Quantum Transport and Thermal Energy Science, School of Physics and Technology, Nanjing Normal University - Nanjing 210023, China
2 Hongzhiwei Technology (Shanghai) Co., Ltd. - Shanghai 201206, China
3 Department of Physics and International Centre for Quantum and Molecular Structures, Shanghai University 99 Shangda Road, Shanghai 200444, China
4 Department of Physics and the Center of Theoretical and Computational Physics, The University of Hong Kong Pokfulam Road, Hong Kong SAR, China
Received: 24 August 2018
Accepted: 15 November 2018
We report the amorphous structure of Al2O3 and the transport properties of the Fe/amorphous Al2O3/Fe magnetic tunnel junction (MTJ) from first principles. The amorphous Al2O3 structure was generated by a heat and quench method via classical molecular dynamics, and the dielectric and transport properties were calculated from first principles. The tunnel magnetoresistance of the Fe/amorphous Al2O3/Fe MTJ is 25% under zero bias and then slightly increases to 28% at the bias of 0.1 V. It then decreases with the increasing bias and becomes negative when the applied bias exceeds 0.4 V due to the rapid increase of the spin-down current in the antiparallel configuration which is originated from the new transmission channel of minority electrons in the left lead introduced by the increasing bias. The spin-injection efficiency (SIE) is also calculated to study the spin-polarized current of the Fe/amorphous Al2O3/Fe system. It is found that the SIE coefficient is around 60% and 15% at equilibrium for the parallel and antiparallel configuration, respectively.
PACS: 61.43.Dq – Amorphous semiconductors, metals, and alloys / 72.25.Mk – Spin transport through interfaces / 85.75.Dd – Magnetic memory using magnetic tunnel junctions
© EPLA, 2018
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