Local disorder and water uptake in La1–xSrxScO3–δ

Abstract

Structure of perovskite oxides La1–xSrxScO3–δ (x=0, 0.04, 0.09) have been studied by X-Ray powder diffraction method. Orthorhombic distortions are found to decrease with increasing of strontium concentration. Water uptake of Sr-doped lanthanum scandates was studied by means of thermogravimetric analysis over the temperature range of 300–950°C in gas mixture with water and oxygen partial pressure of pH2O=0.24 atm and pO2=0.18 atm, respectively. Based on the thermogravimetry data the hydration enthalpy and entropy have been calculated for oxides La1–xSrxScO3–δ (x=0.04, 0.09). 45Sc nuclear magnetic resonance (NMR) spectra were taken at T=300 K and external magnetic field H0=11.7 T. 45Sc NMR study revealed that local symmetry around scandium ions in lanthanum scandate was affected by the presence of both strontium and protonic defects. Possible reasons of 45Sc NMR spectra changes have been considered.