Effective strain manipulation of the antiferromagnetic state of polycrystalline NiO

TL;DR

This paper demonstrates strain manipulation of the antiferromagnetic state in polycrystalline NiO using spin Hall magnetoresistance, providing an energy-efficient on-chip method for magnetic state control relevant for memory applications.

Contribution

It reports the first detection of Neel vector orientation in polycrystalline NiO via SMR and shows strain tuning of magnetic anisotropy using a piezoelectric substrate.

Findings

Strain reduces the critical magnetic field for SMR saturation.

Polycrystalline NiO exhibits positive in-plane magnetostriction.

Strain tuning effectively manipulates the antiferromagnetic state.

Abstract

As a candidate material for applications such as magnetic memory, polycrystalline antiferromagnets offer the same robustness to external magnetic fields, THz spin dynamics, and lack of stray field as their single crystalline counterparts, but without the limitation of epitaxial growth and lattice matched substrates. Here, we first report the detection of the average Neel vector orientiation in polycrystalline NiO via spin Hall magnetoresistance (SMR). Secondly, by applying strain through a piezo-electric substrate, we reduce the critical magnetic field required to reach a saturation of the SMR signal, indicating a change of the anisotropy. Our results are consistent with polycrystalline NiO exhibiting a positive sign of the in-plane magnetostriction. This method of anisotropy-tuning offers an energy efficient, on-chip alternative to manipulate a polycrystalline antiferromagnets magnetic state.