Oxygen-vacancy effect on structural, magnetic, and ferroelectric properties in multiferroic YMnO <inf>3</inf> single crystals

We have investigated the structural, magnetic, and ferroelectric properties of magnetically frustrated multiferroic YMnO 3 single crystals. The ferroelectric domain structures of YMnO 3 samples were studied by piezoresponse force microscopy. Instead of domain vortex structure in stoichiometric crystals, YMnO 3-δ exhibits a random domain configuration with straight domain walls. In magnetic measurements, the YMnO 3-δ crystal shows typical antiferromagnetic behavior with higher Nel temperature and lower magnetization compared to the stoichiometric sample. The ordered oxygen vacancies dominate multiferroicity through tailoring the domain wall structure. © 2012 American Institute of Physics