Evidence of ferroelectricity in ferrimagnetic κ-Al_2O_3-type In_(0.25)Fe_(1.75)O_3 films

摘要

We report direct evidence of the multiferroic nature of the κ-Al_2O_3-type In_xFe_(2-x)O_3 films (x - 0-0.25) grown on the SrTiO_3(111) substrates at room temperature. The κ-Al_2O_3-type In_xFe_(2-x)O_3 films show a clear saturated and opened P-E hysteresis loop at room temperature with a remnant polarization of 1.8 μCcm~(-2) . Also, the ferrimagnetic-incommensurate magnetic phase transition is observed at 205 K, which is compatible with the recent report on the In_(0.24)Fe_(1.16)O_3 nanorods. The results indicate that the substitution of Me~(3+) ion, which has a larger ionic radius than Fe~(3+), is effective to grow good insulating ferroelectric κ-Al_2O_3-type Fe_2O_3 films, leading to the genuine multiferroic nature.