2014/10/02 by Li Ming Loong, Xuepeng Qiu, Zhi Peng Neo +5 · 1 citation
Physics and Astronomy · #cond-mat.mtrl-sci #cond-mat.mes-hall
paper · pdf · doi:10.1038/srep06505
published as Sci. Rep. 4, 6505 (2014)
arxiv created 2014/10/02 · arxiv updated 2014/10/03
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.