Giant spin-torque diode sensitivity at low input power in theabsence of bias magnetic field

Microwave detectors based on the spin-transfer torque diode effect are among the key emerging spintronic devices. By utilizing the spin of electrons in addition to charge, they have the potential to overcome the theoretical performance limits of their semiconductor (Schottky) counterparts, which cannot operate at low input power. Here, we demonstrate nanoscale magnetic tunnel junction microwave detectors, exhibiting record-high detection sensitivity of 75400 mVmW-1 at room temperature, without any external bias fields, for input microwave power down to 10 nW. This sensitivity is 20× and 6× larger than the stateof-
the-art Schottky diode detectors (3800 mVmW-1) and existing spintronic diodes with greater than 1000 Oe magnetic bias (12000 mVmW-1), respectively. Micromagnetic simulations supported by microwave emission measurements reveal the essential role of the injection locking mechanism to achieve this sensitivity performance. The results enable dramatic improvements in the design of low-input-power microwave detectors, with wideranging applications in telecommunications, radars, and smart networks.