Comparison of the Compression Behaviour of BaSnO3 and Ba0.575Sr0.425SnO3

We propose to study the effect of pressure on the structure of the tetragonal Ba0.575Sr0.425SnO3, The behaviour will be compared to the compression of the cubic BaSnO3 (parent compound). At room temperature the perovskite system Ba1-xSrxSnO3 shows a series of phases in the sequence orthorhombic (Pbnm), orthorhombic (Ibmm), tetragonal (I4/mcm), and cubic (Pm-3m) [4]. These are a consequence of the sequential introduction of cooperative tilting of the corner sharing SnO6 octahedra resulting from the changes in the average A site size. Given that the effect of reducing the lanthanide ionic radii is equivalent to that of applyingpressure, it is theoretically possible to study the effect of A-site substitution on the structure using a single compound, hence such high pressure studies are useful for developing such models.