An investigation was made of  the structural, magnetic, and ferroelectric properties of magnetically frustrated multiferroic YMnO3 single crystals. The ferroelectric domain structures of YMnO3 samples were studied by piezoresponse force microscopy. Instead of domain vortex structure in stoichiometric crystals, YMnO3−δ exhibits a random domain configuration with straight domain walls. In magnetic measurements, the YMnO3−δ crystal shows typical antiferromagnetic behavior with higher Néel temperature and lower magnetization compared to the stoichiometric sample. The ordered oxygen vacancies dominate multiferroicity through tailoring the domain wall structure.

Oxygen-Vacancy Effect on Structural, Magnetic, and Ferroelectric Properties in Multiferroic YMnO3 Single Crystals. D.P.Chen, Y.Du, X.L.Wang, Z.X.Cheng, S.X.Dou, Z.W.Lin, J.G.Zhu, B.Xu: Journal of Applied Physics, 2012, 111[7], 07D913