Phase transformation in hexagonal ErMnO3 under high pressure

The pressure-induced phase transition of the hexagonal manganite ErMnO3 has been investigated using the synchrotron x-ray diffraction technique up to 57.6 GPa in a diamond anvil cell. The hexagonal structure exhibits anisotropic compression behavior. The bulk modulus (B-0) is 168(3) GPa with B-0' = 4.0 (fixed). At room temperature, ErMnO3 undergoes a hexagonal-to-orthorhombic phase transition at similar to 20.2 GPa, but coexists with the orthorhombic phase up to the highest pressure of 57.6 GPa. When laser-heated to 1500-2000 K, the hexagonal ErMnO3 transforms to a denser orthorhombic perovskite structure completely at similar to 17 GPa, accompanied by similar to 11% volume reduction. The distortion and tilts of the octahedra MnO6 in the orthorhombic structure decrease with increasing pressure. The bulk modulus of the orthorhombic structure is 214(4) GPa with B-0' = 4.0 (fixed), larger than that of the hexagonal structure. The orthorhombic structure ErMnO3 is stable at least up to similar to 45 GPa and can be quenched. (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.4768285]