X-Ray investigations of the crystal structure and phase transitions of YMnO3

Lattice constants and atomic parameters of YMnO 3 were investigated from room temperature up to 1010°C. Lattice constant c decreases slowly with temperature, contrary to earlier publication. With rising temperature small changes of the crystal structure were observed. The paraelectric phase is probably disordered and the phase transition is rather diffuse. At 1000°C we found a new phase transition resulting in the crystal structure with a small hexagonal lattice cell with a = 3.61 Å, c = 11.39 Å, Z = 2, space group P6 3 /mmc D 4 6h Atomic parameters of this high temperature crystal structure are presented.