X-ray Diffraction Study on Charge and Orbital Order in Pr_0.65Ca_0.35MnO₃ under High Pressure

抄録

X-ray diffraction measurements have been performed on Pr_0.65Ca_0.35MnO₃ under hydrostatic pressure. Superlattice reflections due to charge and orbital order were measured at various temperatures and pressures. Above 2.1 GPa, the superlattice reflections disappear at low temperatures, showing a transition to a charge and orbital disordered phase. We found a pressure-induced phase characterized by a significant change in the intensity of the superlattice reflection. This phase shows reentrant transition behavior. Possible types of orders of the pressure-induced phase are discussed. The diffuse peaks associated with the short-range order observed under pressure is also presented.