The Voltage-Controlled Magnetic Anisotropy Effect Under High Electric Field

The discovery of voltage-controlled magnetic anisotropy (VCMA) effect in perpendicular magnetic tunneling junction (pMTJ) has attracted considerable interests for low-power and high-speed memory application. In a recent DFT study¹, the VCMA effect is expected to diverge from commonly observed linear PMA vs E-field relation and exhibit nonlinearity under high E-field. However, limitations of established methods make high E-field unattainable.

Modified TMR method is performed in this work. By using pulsed voltage, on-time can be reduced by at least 2 orders of magnitude, which increases the MTJ breakdown voltage and allows for higher E-field (>800mV/nm). Unexpected magnetoresistance independent of relative FM spin alignment was discovered and attributed to impurity-assisted tunneling. Efforts were made to exclude it from conventional TMR and a nonlinear E-field dependence of PMA can be observed under high bias. Electron doping with different metals as buffer and insertion is carried out and their influence is reported and compared with DFT study.


1. J. Zhang, P. V. Lukashev, S. S. Jaswal, and E. Y. Tsymbal, Phys. Rev. B 96, 014435 (2017).