Time-resolved imaging of magnetoelectric switching in multiferroic MnWO4

We show that the electric-field-induced reversal of the magnetic order parameter in multiferroic MnWO4 occurs on the time scale of milliseconds. Throughout the switching process the magnetic order and the magnetically induced electric polarization remain rigidly coupled. The temporal progression of the domain structure was imaged with nanosecond resolution by an electrical-pump-optical-probe technique using optical second harmonic generation. The nonequilibrium domain pattern significantly differs from the one during quasistatic domain reversal. A qualitative model gives an estimate of why the magnetoelectric order-parameter reversal in the magnetically induced ferroelectrics is not inherently ultrafast.