Oakland University, 2200 North Squirrel Rd., Rochester MI 48309, U.S.A.
Received December 21, 2014
The spin-transfer torque (STT) effect provides a new method of manipulation of magnetization in nanoscale objects. The STT effect manifests itself as a transfer of spin angular momentum between the parallel magnetic layers separated by a nonmagnetic spacer and traversed by a dc electric current. The transfer of the spin angular momentum from one layer to another could result in the excitation of the microwave-frequency magnetization dynamics in one of the magnetic layers. On the other hand, when a magnetization dynamics is excited in a magnetic layered structure by an external microwave signal both the structure electrical resistance and current through the structure will acquire microwave components resulting in the appearance of a rectified dc voltage on the magnetic structure. This “spin-torque diode effect” can be used for the development of ultra-sensitive spintorque microwave detectors (STMD). Below we present a brief review of our recent work on the general properties of STMDs, analyze the performance of the “resonance-type” and “threshold-type STMD” and consider the possible applications for such microwave detectors.
PACS: 85.75.–d Magnetoelectronics: devices exploiting spin polarized transport or integrated magnetic fields; PACS: 75.76.+j Spin transport effects; PACS: 07.57.Kp Bolometers; infrared, submillimeter wave, microwave, and radiowave receivers and detectors.