Studies of ferroelectric and magnetic phase transitions in Pb(Fe_0.5Nb_0.5)_1-xCe_xO₃ multiferroic ceramics

Multiferroic Pb(Fe0.5Nb0.5)1-xCexO3 (x = 0.025, 0.05, 0.075, 0.10) ceramic compositions were prepared by solid state synthesis and usual sintering. XRD studies have shown a formation of the perovskite structure in all the compositions studied. However a small amount of pyrochlore phase was detected in Ce-doped compositions with x ≥ 0.075. Scanning electron microscopy studies and elemental analysis have shown that at the boundaries of the large grains of nearly pure PbFe0.5Nb0.5O3 there exist a lot of small submicron grains enriched by Ce. Concentration dependencies of the unit-cell parameter and temperatures of ferroelectric and magnetic phase transitions also imply that solubility of Ce in PFN does not exceed ≈ 2 at.%.