Magnetostriction-polarization coupling in multiferroic MnMnWO.

Double corundum-related polar magnets are promising materials for multiferroic and magnetoelectric applications in spintronics. However, their design and synthesis is a challenge, and magnetoelectric coupling has only been observed in NiTeO among the known double corundum compounds to date. Here we address the high-pressure synthesis of a new polar and antiferromagnetic corundum derivative MnMnWO, which adopts the NiTeO-type structure with low temperature first-order field-induced metamagnetic phase transitions (T  = 58 K) and high spontaneous polarization (~ 63.3 μC·cm). The magnetostriction-polarization coupling in MnMnWO is evidenced by second harmonic generation effect, and corroborated by magnetic-field-dependent pyroresponse behavior, which together with the magnetic-field-dependent polarization and dielectric measurements, qualitatively indicate magnetoelectric coupling. Piezoresponse force microscopy imaging and spectroscopy studies on MnMnWO show switchable polarization, which motivates further exploration on magnetoelectric effect in single crystal/thin film specimens.