Magnetoresistance in Metallic Ferroelectrics

TL;DR

This paper reports the coexistence of ferroelectricity and magnetoresistance in metallic PbNb0.12Ti0.88O3 thin films, revealing unique asymmetric magnetic responses and potential for multifunctional device applications.

Contribution

It demonstrates the experimental realization of ferroelectricity with magnetic responses in a conducting metallic material, a significant advancement in multiferroic research.

Findings

Negative MR up to 50% observed under in-plane magnetic field

MR switches to positive when magnetic field is parallel to surface normal

Unique asymmetric magnetic responses linked to electron spin interactions

Abstract

Polar metals with ferroelectric-like displacements in metals have been achieved recently, half century later than Anderson and Blount's prediction. However, the genuine ferroelectricity with electrical dipolar switching has not yet been attained experimentally in the conducting materials, especially the ones possessing magnetic responses. Here we report the coexistence of ferroelectricity and magnetoresistance (MR) in the metallic PbNb0.12Ti0.88O3 (PNTO) thin films. We found that the conducting and magnetic responses of PNTO films are highly asymmetric. Negative MR up to 50% is observed under an in-plane magnetic field; the MR switches to positive with the magnetic field applied parallel to the surface normal. Such unique behavior is attributed to the moving electron caused effective magnetic field which couples with the spins of electrons, which form a dynamic multiferroic state in the metallic PNTO. These findings break a path to multiferroic metal and offer a great potential to the multi-functional devices.