Preparation, structure and electrical conductivity of pyrochlore-type samarium-lanthanum zirconate ceramics

A series of zirconate compounds with the general formula Sm_2-xLa_xZr₂O₇ (0≤x≤1.0) were prepared by pressureless-sintering method at 1973K for 10h in air. The relative density, structure and electrical conductivity of Sm_2-xLa_xZr₂O₇ ceramics were investigated by the Archimedes method, X-ray diffraction and impedance spectroscopy measurements. Sm_2-xLa_xZr₂O₇ (0≤x≤1.0) ceramics exhibit a pyrochlore-type structure. The measured electrical conductivity of Sm_2-xLa_xZr₂O₇ ceramics obeys the Arrhenius relation and gradually increases with increasing temperature from 673 to 1173K. Sm_2-xLa_xZr₂O₇ ceramics are oxide-ion conductors in the oxygen partial pressure range of 1.0×10^-4 to 1.0atm at all test temperature levels. The electrical conductivity of Sm_2-xLa_xZr₂O₇ ceramics decreases with increasing lanthanum content at identical temperature levels.