Mössbauer Study of the Effect of Cation Substitutions on the Magnetic Phase Transitions in BiFe1 – xCrxO3 and (1 – x)BiFeO3–xPbFe0.5Sb0.5O3 Solid Solutions

The concentration dependences of the magnetic phase transition temperature TN, determined based on the changes in Mossbauer spectra, were investigated for a BiFeO3 solid solution with ordered perovskite PbFe0.5Sb0.5O3 and for a disordered BiFe1 – xCrxO3 solid solution. It is established that the magnetic-order type in BiFe1 – xCrxO3 changes from antiferromagnetic to spin-glass at a higher degree of Fe-sublattice dilution in comparison with the PbFe0.5Nb0.5O3-based solid solutions presumably because of the smaller BiFeO3 lattice parameter. Due to the local ordering of Fe3+ and Sb5+ ions, the TN value decreases more rapidly (as compared to BiFe1 – xCrxO3) with a decrease in the Fe3+ content in the lattice of (1 – x)BiFeO3– xPbFe0.5Sb0.5O3 solid solutions.