High sensitivity microwave detection using a magnetic tunnel junction in the absence of an external applied magnetic field

TL;DR

This paper demonstrates that magnetic tunnel junctions can detect broadband microwave signals with high sensitivity without external magnetic fields, enhanced by bias current, due to their nonlinear conductance.

Contribution

It introduces a novel microwave detection method using MTJs without external magnetic fields and explains the enhancement mechanism via nonlinear resistance.

Findings

MTJs produce significant voltage signals under microwave radiation without external magnetic fields.

Bias current increases the detection sensitivity by an order of magnitude.

Estimated sensitivity for optimized MTJs is about 5,000 mV/mW.

Abstract

In the absence of any external applied magnetic field, we have found that a magnetic tunnel junction (MTJ) can produce a significant output direct voltage under microwave radiation at frequencies, which are far from the ferromagnetic resonance condition, and this voltage signal can be increase by at least an order of magnitude by applying a direct current bias. The enhancement of the microwave detection can be explained by the nonlinear resistance/conductance of the MTJs. Our estimation suggests that optimized MTJs should achieve sensitivities for non-resonant broadband microwave detection of about 5,000 mV/mW.