Role of local structural distortion in driving ferroelectricity in GdCrO3

Abstract

Temperature dependent synchrotron x-ray diffraction and extended x-ray absorption fine structure (EXAFS) studies were performed to understand the role of structural characteristics in driving the magnetoelectric mul- tiferoic properties of GdCrO3. The results suggest that the distortion in the structure appears to be associated with the off-center displacement of Gd-atoms together with octahedral rotations via displacement of the oxygen ions in GdCrO3. In addition, the magnetic coupling below magnetic transition temperature leads to additional distortion in the system via magnetostriction effect, playing a complementary role in the enhancement of ferro- electric polarization. Further, a comparative EXAFS study of GdCrO3 with a similar system YCrO3 suggests that oxygen environment of Gd in GdCrO3 is different from Y in YCrO3, which resulting in an orthorhombic P na21 structure in GdCrO3 in contrast to the monoclinic P 21 structure in YCrO3 .