Powder diffraction studies of pressure- induced instabilities in orthorhombic LnGаО_3

摘要

Pressure evolution of LaGaO_3, CeGaO_3, РгGaO_3, NdGaO3, La_(0.75)Pr_(0.25)GaO_3andLa_(0.63)Nd_(0.37)GaO_3crystal structures was studied using powder diffraction with synchrotronradiation at ambient temperature in a broad pressure range. Structural instabilities corres-ponding to phase transformations have been observed in all studied compositions and it wasfound that P_cof these transitions depends on the deformation of perovskite structure. Theeffect of the pressure medium on the phase transition, bulk modulus and compressibilities ofLaGaO_3, CeGaO_3, PrGаО_3,NdGaO_3,La_(0.75)Pr_(0.25)GaO_3 andLa_(0.63)Nd_(0.37)GaO_3has been dis-cussed in brief.