Structural Characterisation of PrBCNO and Pr_{1. 2}SCNO

抄録

The crystal structures of Pr_{1. 2}Sr_{1. 8}Cu_{2. 2}Nb_{0. 8}O_8-y (Pr_{1. 2}SCNO) and PrBa₂Cu₂NbO_8-y (PrBCNO) have been determined from X-ray powder diffraction spectra recorded in the pressure range up to 60 GPa. Both samples have a tetragonal structure at ambient pressure. PrBCNO was found to have an orthorhombic high-pressure phase, the transition pressure being 13 GPa. The bulk moduli evaluated at zero pressure are 212 GPa and 215 GPa for Pr_{1. 2}SCNO and PrBCNO, respectively.