title: Pressure-induced structural change in orthorhombic perovskite GdMnO3.
abstract: Structural stability of the perovskite-type GdMnO(3) has been investigated by the synchrotron angle-dispersive x-ray diffraction technique up to 63 GPa in a diamond anvil cell. GdMnO(3) stays in an orthorhombic structure but undergoes an isostructural phase transition with ~5% volume reduction at 50 GPa. In the parent orthorhombic phase, the compressions along a, b and c axes exhibit a large anisotropic behavior. With increasing pressure, our results show that the distortion and tilts of the MnO(6) octahedra are reduced continuously and the orthorhombic structure evolves towards higher symmetry. By fitting the observed pressure-volume data using the third-order Birch-Murnaghan equation of state, we obtain the bulk modulus B(0) = 156(3) GPa with B(0)' = 6.5(3) for the starting orthorhombic phase. Upon decompression, the starting orthorhombic phase is recovered.
authors.affiliation: Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049, People's Republic of China.
authors.forename: Chuanlong
authors.initials: C
authors.lastname: Lin
authors.forename: Yufeng
authors.initials: Y
authors.lastname: Zhang
authors.forename: Jing
authors.initials: J
authors.lastname: Liu
authors.forename: Xiaodong
authors.initials: X
authors.lastname: Li
authors.forename: Yanchun
authors.initials: Y
authors.lastname: Li
authors.forename: Linyun
authors.initials: L
authors.lastname: Tang
authors.forename: Lun
authors.initials: L
authors.lastname: Xiong