Local structures of Sr2FeMnO5+y (y=0, 0.5) and Sr2Fe1.5Cr0.5O5 from reverse Monte Carlo modeling of pair distribution function data and implications for magnetic order

The local structures of the oxygen deficient perovskites Sr2FeMnO5, Sr2FeMnO5.5, and Sr2Fe1.5Cr0.5O5 have been analyzed using neutron pair distribution function data. The results show that locally all three structures are more complex than implied by their average cubic structures and that the distributions of oxygen vacancies are not completely random on a local level. For both Sr2FeMnO5+y compounds it is found that there is no short range …