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

TL;DR

This paper reports a nanoscale spin-torque diode microwave detector with record-high sensitivity at room temperature, operating without external magnetic bias and at very low input power, surpassing traditional semiconductor and prior spintronic devices.

Contribution

The study demonstrates a highly sensitive, bias-free spin-torque diode microwave detector with record sensitivity at low power, advancing spintronic device performance without external magnetic fields.

Findings

Record-high sensitivity of 75400 mV/mW at room temperature.

Operates effectively at input powers as low as 10 nW.

Outperforms state-of-the-art Schottky and biased spintronic diodes.

Abstract

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 microwave detectors exhibiting record-high detection sensitivity of 75400 mV mW$^{-1}$ at room temperature, without any external bias fields, for input microwave power down to 10 nW. This sensitivity is 20x and 6x larger than state-of-the-art Schottky diode detectors (3800 mV mW$^{-1}$) and existing spintronic diodes with >1000 Oe magnetic bias (12000 mV mW$^{-1}$), respectively. Micromagnetic simulations supported by microwave emission measurements reveal the essential role of the injection locking to achieve this sensitivity performance. The results enable dramatic improvements in the design of low input power microwave detectors, with wide-ranging applications in telecommunications, radars, and smart networks.