Electrical manipulation of a ferromagnet by an antiferromagnet

TL;DR

This study demonstrates that an antiferromagnet can efficiently manipulate a ferromagnet electrically via spin torque, with potential for advanced spintronic devices, driven by the antiferromagnetic order and exchange bias.

Contribution

It introduces a novel method of electrical control of ferromagnets using antiferromagnets, showing enhanced spin torque effects linked to exchange bias and antiferromagnetic order.

Findings

Antiferromagnet can generate antidamping-like spin torque on ferromagnet.

Effective spin-Hall angle exceeds that of many heavy metals.

Exchange bias correlates with increased torque efficiency.

Abstract

We demonstrate that an antiferromagnet can be employed for a highly efficient electrical manipulation of a ferromagnet. In our study we use an electrical detection technique of the ferromagnetic resonance driven by an in-plane ac-current in a NiFe/IrMn bilayer. At room temperature, we observe antidamping-like spin torque acting on the NiFe ferromagnet, generated by the in-plane current driven through the IrMn antiferromagnet. A large enhancement of the torque, characterized by an effective spin-Hall angle exceeding most heavy transition metals, correlates with the presence of the exchange-bias field at the NiFe/IrMn interface. It highlights that, in addition to strong spin-orbit coupling, the antiferromagnetic order in IrMn governs the observed phenomenon.