First order orthorhombic-to-tetragonal phase transition in Sr0.5Ba0.5HfO3

High resolution synchrotron X-ray diffraction methods have been used to study the crystal structure of Sr0.5Ba0.5HfO3 (SBH). These measurements have demonstrated the co-existence of the orthorhombic (Imma) and tetragonal (I4/mcm) phases in SBH. As the sample is cooled from room temperature to 20 K, the amount of the tetragonal phase present rapidly decreases due to the first order phase transition.