Investigation of the magnetic and the ferroelectric properties of BiMnO_3 thin films

摘要

We have synthesized high-quality BiMnO_3 thin films on Nb-doped SrTiO_3 substrates with (100), (110), and (111) orientations. All the films with different orientations undergo ferromagnetic transitions at approximately the same temperature (～105 K) as bulk BiMnO_3 does. The magnetic easy direction was also found to be the monoclinic [010]_m direction in accordance with the bulk case. Detailed measurements of ferroelectric characteristics such as the P - E hysteresis loops and the piezoelectric coefficient d _(33) did not show any significant evidence of ferroelectricity in any of the films.