A CMOS-compatible, scalable and compact magnetoelectric spin-torque microwave detector

The development of compact and highly sensitive microwave detectors compatible with complementary metal-oxide-semiconductor (CMOS) processes remains a major challenge in microwave technology. Spin-torque diodes are emerging nanoscale spintronic devices capable of surpassing the theoretical thermodynamic sensitivity limits of Schottky diodes. However, their practical use in compact systems is limited by the need for external antennas or probes. Here we demonstrate a magnetoelectric (ME) spin-torque microwave detector that monolithically integrates a ME antenna with a magnetic tunnel junction (MTJ). The device directly converts wireless electromagnetic signals into a d.c. output at sub-microwatt power levels, achieving a sensitivity greater than 90 kV W^-1, a noise equivalent power of 3 pW Hz^-1/2 and a compact footprint of 0.4 mm². This performance is due to the non-linear coupling between incoherent magnetization dynamics, driven by a d.c. current in the MTJ, and the combined effects of the microwave voltage and strain generated by the ME antenna under incident electromagnetic waves. We further show that this design is scalable, enabling the cointegration of a ME antenna with an array of MTJs. A detector incorporating four MTJs exhibits an increased sensitivity exceeding 400 kV W^-1. Our results may contribute to the development of a new generation of highly sensitive, compact and scalable microwave detectors that combine ME antennas and spintronic diodes.