Time-resolved imaging of magnetoelectric domain switching in multiferroic MnWO4

TL;DR

This study uses time-resolved optical techniques to observe millisecond-scale electric-field-induced magnetic domain switching in multiferroic MnWO4, revealing the dynamics and coupling of magnetic and electric orders.

Contribution

It provides the first direct, nanosecond-resolution imaging of domain evolution during electric-field switching in MnWO4, explaining why the process is not ultrafast.

Findings

Magnetic domain reversal occurs on the millisecond timescale.

Magnetization remains rigidly coupled to electric polarization during switching.

The reversal process is slower than in some other multiferroics due to intrinsic material properties.

Abstract

By an electrical-pump--optical-probe technique we show that the electric-field-induced reversal of the magnetic order parameter in multiferroic MnWO$_4$ occurs on the time scale of milliseconds and maintains a rigid coupling of the magnetization to the magnetically induced electric polarization. The temporal progression of the spatially resolved domain structure was imaged with nanosecond resolution by optical second harmonic generation and compared to the quasi-static domain reversal. A qualitative model gives an estimate of why the magnetoelectric order-parameter reversal in the magnetically induced ferroelectrics is not inherently ultrafast.