The room temperature crystal structure of the perovskite Pr0.5Sr0.5MnO3

Using both powder and single crystal neutron diffraction we have determined the room temperature structure of Pr0.5Sr0.5MnO3 from melt-grown crystalline material. Contrary to previous measurements on polycrystalline samples we find the room temperature structure of Pr0.5Sr0.5MnO3 is tetragonal, space group F4/mmc (a = 7.64093(5) Angstrom, c = 7.79104(8) Angstrom), The structure of Pr0.5Sr0.5MnO3 is related to the ideal primitive cubic perovskite structure by a single correlated rotation of MnO6 octahedra about the c axis. We find that MnO6 octahedra exhibit a small Jahn-Teller distortion (Delta(Mn-O) approximate to 0.02 Angstrom). (C) 1996 Academic Press, Inc.