Crystal Structures and Phase Transitions in the SrTiO_3-SrZrO_3 Solid Solution

摘要

Laboratory and synchrotron X-ray powder diffraction and neutron powder diffraction have been used to determine crystal structures in the perovskites SrTixZr l-xO3. Superlattice reflec- tions in the neutron diffraction patterns proved to be the most reliable indicators of lower symmetry structures. The room tem- perature structures are orthorhombic Pbnm in the range of 0 <= x <= 0.4, tetragonal 14/mcm in the range <= x <= 0.95, and cubic PmJm for 0.95<= x <= I. 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 temp- eratures, using neutron diffraction methods, where the transition tetragonal to cubic was noted. Measurements at low temp- eratures using synchrotron X-ray powder diffraction are re- ported.