The use of the spin-diode effect in magnetic tunnel junctions under the current-induced transfer of spin angular momentum opens the prospect of the significant increase in the microwave sensitivity compared to Schottky semiconductor diodes in the GHz frequency range. Theoretical analysis of diode rectification effect of the microwave signal in the magnetic tunnel junction (spin-diode effect) has been performed under resonant excitation of spin waves in the free magnetic layer as a result of the current-induced spin-transfer torque effect. Within the linear macrospin approximation the frequency characteristics of resonant response of the spin-torque diode on the microwave signal have been calculated depending on the direction and amplitude of the applied magnetic field and bias current. It has been shown that in absence of bias current the maximum value of the rectified DC bias voltage across the junction is achieved in the case of mutually perpendicular magnetization geometry in its magnetic layers and drops with increasing the resonant frequency of oscillations in the magnetic field while maintaining the equilibrium spin orientation in the layers. When applying the bias current the resonance amplitude of forced spin oscillations dramatically increases under the microwave excitation when approaching the critical point of spin state stability of the spin-torque diode, in which the linewidth is only limited by the nonlinear effects. The increase in the spin-torque diode sensitivity is very important for its application in the systems of microwave holographic vision.
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