Field-angle and DC-bias dependence of spin-torque diode in giant magnetoresistive microstripe

The spintorque diode effect in all metal spintronic devices has been proposed as amicrowave detector with a high power limit and resistivity to breakdown. The previous works have revealed the field-angle dependence of the rectified DC voltage (VDC) in theferromagnetic stripe. The giantmagnetoresistive(GMR) microstripe exhibits higher sensitivity compared with theferromagnetic stripe. However, the influence of themagnetic field direction and bias current in the spinrectification ofGMR microstripe is not yet reported. In this work, the angular dependence and bias dependence of resonant frequency (fR) andVDC are investigated. A macrospin model concerning the contribution ofmagnetic field, shapeanisotropy, and unidirectionalanisotropy is engaged to interpret the experimental data.fR exhibits a |sin  δH| dependence on the in-plane field angle (δH).VDC presents either |sin  δH| or |sin2  δH cos δH | relation, depending on the magnitude ofHext. OptimizedVDC of 24  μV is achieved under 4  mTmagnetic field applied atδH = 170°. Under out-of-planemagnetic field,fR shows a cos  2θH reliance on the polar angle (θH), whereasVDC is sin  θH dependent. The Oersted field of the DC bias current (IDC) modifies the effective field, resulting in shiftedfR. EnhancedVDC with increasingIDC is attributed to the elevated contribution of spin-transfertorque. MaximumVDC of 35.2  μV is achieved, corresponding to 47% increase compared with the optimized value under zero ...

Source: Applied Physics Letters - November 7, 2016 Category: Physics Authors: X. Li, Y. Zhou, C. Zheng, P. H. Chan, M. Chan and Philip W. T. Pong Source Type: research