Crystal and magnetic structure of (1 - X) ^{BiFeO 3}-x ^{SrTiO 3} (x=0.2, 0.3, 0.4 and 0.8)

The effect of doping SrTiO₃ into BiFeO₃ on the magnetic and crystal structure has been explored using powder neutron diffraction for (1-x)^BiFeO3-x^SrTiO3 where x=0.2, 0.3, 0.4, 0.6 and 0.8. While the data are not sensitive to the cycloidal component of the magnetic ordering, the evolution of the collinear antiferromagnetic moment of the G-type antiferromagnetic component with T and x has been explored, as have structural parameters. It is found that for x≤0.4 pure phase samples form in the R3c cell, and for x=0.8 a non-magnetic Pm3̄m phase is obtained. The x=0.6 sample gives a mixed phase. Through the R3c phase the magnetic structure does not change appreciably apart from the reduction of magnetic moment magnitude with the increasing T and/or x.