Phonon Scattering by Paramagnetic Ions of Europium and Samarium in Bismuth Ferrite

Temperature dependences of the thermal diffusivity and thermal conductivity in multiferroic materials BiFeO3, Bi0.90Sm0.10FeO3, and Bi0.90Eu0.10FeO3 were studied. Substitution of rare-earth ions of europium and samarium for bismuth ions in bismuth ferrite was found to decrease the phonon thermal conductivity in a wide temperature range. The decrease in the heat conductivity of bismuth ferrite was determined to result from resonance phonon scattering by paramagnetic ions of europium and samarium.