title: Oxygen content, crystal structure and chemical expansion of PrBaCo(2-x)Fe(x)O(6-δ) double perovskites.
abstract: PrBaCo2-xFexO6-δ (x = 0-0.6) double perovskites were shown to have a tetragonal P4/mmm structure in air over the complete temperature range investigated despite the oxygen content reaching a threshold value of 5.5 at temperatures from 850 °C for x = 0 up to 1078 °C for x = 0.6. However the P4/mmm→Pmmm structure transition was found to occur in PrBaCo2O6-δ under reducing conditions at temperatures from 500 °C at pO2 = 10(-3) atm down to 350 °C at pO2 = 10(-4) atm. The lattice chemical expansion along the a-axis and contraction along the c-axis, with decreasing oxygen content, 6 - δ, were found to completely compensate each other in the double perovskites and, therefore, their volume chemical expansion became negligible. As a result the cell volume linearly increases with temperature contrary to simple cubic perovskites.
authors: Department of Chemistry, Institute of Natural Sciences, Ural Federal University, Ekaterinburg, 620000, Russia. dmitry.tsvetkov@urfu.ru.
authors: D S
authors: DS
authors: Tsvetkov
authors: I L
authors: IL
authors: Ivanov
authors: D A
authors: DA
authors: Malyshkin
authors: A Yu
authors: AY
authors: Zuev
mesh_terms: D017610:Calcium Compounds / Q000737:chemistry*; D002152:Calorimetry, Differential Scanning; D003460:Crystallization; D015394:Molecular Structure; D010087:Oxides / Q000737:chemistry*; D010100:Oxygen / Q000737:chemistry*; D013696:Temperature; D014025:Titanium / Q000737:chemistry*; D014961:X-Ray Diffraction
chemical_list: D017610:Calcium Compounds; D010087:Oxides; C059910:perovskite; D014025:Titanium; D010100:Oxygen