Enhancement of microwave detection sensitivity in un-biased perpendicular magnetic tunnel junctions using voltage controlled magnetic anisotropy

摘要

We perform a numerical study of microwave detection using an unbiased magnetic tunnel junction with a perpendicularly magnetized free layer by utilizing the phenomena of Voltage Control Magnetic Anisotropy (VCMA). We show that the field angle for achieving maximum sensitivity is significantly affected by the presence of the VCMA effect. The combination of VCMA effect and spin-transfer torque (STT) enhances the maximum sensitivity by ＞ 30% compared to the case of pure STT. We explain this behavior using the symmetric voltage component that arises solely due to the VCMA effect in the spin-torque ferromagnetic resonance spectra. We also show the presence of meta-stable states at the low field for which the sensitivity in the presence of the VCMA effect is enhanced by ～70%. For the chosen device parameters, we predict a maximum sensitivity value of 1400 mV/mW, which is comparable to commercial semiconductor-based unbiased Schottky detectors.