Oxide perovskites: pressure derivatives of the bulk and shear moduli

The pressure derivatives of elastic moduli (partial derivative M/ partial d erivative P: M=K-s and G) for a suite of polycrystalline oxide perovskites (2 titanates, 1 stannate and 2 aluminates) have been measured up to 3 GPa u sing the ultrasonic interferometry method combined with a buffer rod techni que. Two empirical systematic relationships (partial derivative G/partial d erivative P vs K-s/G and partial derivative K-s/partial derivative P vs K-s (M/rho)(1/3)) have been used to investigate the elasticity systematics of this suite of perovskites and to estimate partial derivative M/partial deri vative P of MgSiO3 perovskite. The pressure derivatives partial derivative G/partial derivative P and partial derivative K-s/partial derivative P for this suite of perovskites scatter between well-defined linear trends for th e rutile. rocksalt and spinel structures. The mon diffuse trends observed f or the perovskites might reflect greater flexibility in the response of its corner-connected octahedral framework structure to changing pressure. The pressure derivatives of the elastic moduli for MgSiO3 perovskite estimated by the "perovskite bands" are partial derivative G/partial derivative P=1.6 -2.2 and partial derivative K-s/partial derivative P=3.9-4.2.