Composition and temperature dependent phase transitions in Co W double perovskites, a synchrotron X-ray and neutron powder diffraction study

摘要: Abstract High-resolution synchrotron and neutron powder diffraction techniques were used to determine precise structures for the series of perovskite oxides A 2− x Sr CoWO 6 ( Ca, or Ba, 0⩽ ⩽2). The studies demonstrated that symmetry decreases as average size -site cation with a sequential introduction in-phase out-of-phase tilting BO octahedra. cubic structure in Fm 3¯ m rock-salt like ordering Co W cations was formed Ba ∼ I 4/ ultimately monoclinic P 2 1 / n . mixture tetragonal phases occurs at room temperature but this purely 20 K.