Magnetoelectric coupling in multiferroics probed by optical second harmonic generation

Abstract

Magnetoelectric coupling, as a fundamental physical nature and with the potential to add functionality to devices while also reducing energy consumption, has been challenging to be probed in freestanding membranes or two-dimensional materials due to their instability and fragility. In this paper, we report a magnetoelectric coupling probed by optical second harmonic generation with external magnetic field, and show the manipulation of the ferroelectric and antiferromagnetic orders by the magnetic and thermal fields in BiFeO ₃ films epitaxially grown on the substrates and in the freestanding ones. Here we define an optical magnetoelectric-coupling constant, denoting the ability of controlling light-induced nonlinear polarization by the magnetic field, and found the magnetoelectric-coupling was suppressed by strain releasing but remain robust against thermal fluctuation for freestanding BiFeO ₃.

Abstract

Here, the authors probe a magneto-electric coupling in freestanding BiFeO ₃ by optical second harmonic generation with varying magnetic field and temperature. They find the coupling to be suppressed by strain releasing whereas it remains robust against thermal fluctuations.