title: Strain-enhanced tunneling magnetoresistance in MgO magnetic tunnel junctions.
abstract: While the effects of lattice mismatch-induced strain, mechanical strain, as well as the intrinsic strain of thin films are sometimes detrimental, resulting in mechanical deformation and failure, strain can also be usefully harnessed for applications such as data storage, transistors, solar cells, and strain gauges, among other things. Here, we demonstrate that quantum transport across magnetic tunnel junctions (MTJs) can be significantly affected by the introduction of controllable mechanical strain, achieving an enhancement factor of ~2 in the experimental tunneling magnetoresistance (TMR) ratio. We further correlate this strain-enhanced TMR with coherent spin tunneling through the MgO barrier. Moreover, the strain-enhanced TMR is analyzed using non-equilibrium Green's function (NEGF) quantum transport calculations. Our results help elucidate the TMR mechanism at the atomic level and can provide a new way to enhance, as well as tune, the quantum properties in nanoscale materials and devices.
authors.affiliation: Department of Electrical and Computer Engineering, National University of Singapore, 117576 Singapore.
authors.forename: Li Ming
authors.initials: LM
authors.lastname: Loong
authors.affiliation: Department of Electrical and Computer Engineering, National University of Singapore, 117576 Singapore.
authors.forename: Xuepeng
authors.initials: X
authors.lastname: Qiu
authors.affiliation: Department of Chemical and Biomolecular Engineering, National University of Singapore, 117576 Singapore.
authors.forename: Zhi Peng
authors.initials: ZP
authors.lastname: Neo
authors.affiliation: Department of Electrical and Computer Engineering, National University of Singapore, 117576 Singapore.
authors.forename: Praveen
authors.initials: P
authors.lastname: Deorani
authors.affiliation: Department of Electrical and Computer Engineering, National University of Singapore, 117576 Singapore.
authors.forename: Yang
authors.initials: Y
authors.lastname: Wu
authors.affiliation: Department of Electrical and Computer Engineering, National University of Singapore, 117576 Singapore.
authors.forename: Charanjit S
authors.initials: CS
authors.lastname: Bhatia
authors.affiliation: Department of Chemical and Biomolecular Engineering, National University of Singapore, 117576 Singapore.
authors.forename: Mark
authors.initials: M
authors.lastname: Saeys
authors.affiliation: Department of Electrical and Computer Engineering, National University of Singapore, 117576 Singapore.
authors.forename: Hyunsoo
authors.initials: H
authors.lastname: Yang