Field dependence of magnetic correlations through the polarization flop transition in multiferroic TbMnO3 : evidence for a magnetic memory effect

TL;DR

This study investigates the magnetic and multiferroic transitions in TbMnO3 using neutron scattering, revealing a hysteresis, a magnetic memory effect, and the role of inverse Dzyaloshinski-Moriya coupling in the magnetoelectric response.

Contribution

It provides new evidence of a magnetic memory effect and details the magnetic excitations associated with the polarization flop transition in TbMnO3.

Findings

Observation of hysteresis and memory effect in magnetic transition

Identification of electromagnon in high-field phase

Confirmation of inverse Dzyaloshinski-Moriya coupling role

Abstract

The field-induced multiferroic transition in TbMnO3 has been studied by neutron scattering. Apart strong hysteresis, the magnetic transition associated with the flop of electronic polarization exhibits a memory effect: after a field sweep, TbMnO3 does not exhibit the same phase as that obtained by zero-field cooling. The strong changes in the magnetic excitations across the transition perfectly agree with a rotation of the cycloidal spiral plane indicating that the inverse Dzyaloshinski-Moriya coupling causes the giant magnetoelectric effect at the field-induced transition. The analysis of the zone-center magnetic excitations identifies the electromagnon of the multiferroic high-field phase.