Crystal Structures and Phase Transitions in the SrTiO

Laboratory and synchrotron X-ray powder diffraction and neutron powder diffraction have been used to determine crystal structures in the perovskites SrTixZr1-xO3. Superlattice reflections in the neutron diffraction patterns proved to be the most reliable indicators of lower symmetry structures. The room temperature structures are orthorhombic Pbnm in the range of 0 ≤ x ≤ 0.4, tetragonal I4/mcm in the range 0.4 < x ≤ 0.95, and cubic Pmm for 0.95 < x ≤ 1. Additional measurements were made on the room-temperature tetragonal samples at x=0.5, 0.75, and 0.9. The first two were examined at elevated temperatures, using neutron diffraction methods, where the transition tetragonal to cubic was noted. Measurements at low temperatures using synchrotron X-ray powder diffraction are reported