Specific Heat of CoFe2O4 and the 0.3CoFe2O4–0.7PbTiO3 Composite

Abstract

The temperature dependence of the specific heat of the CoFe₂O₄ ferromagnet and the 0.3CoFe₂O₄–0.7PbTiO₃ muliferroic composite is studied in the temperature range 150–820 K. An addition of lead titanate ferroelectric to cobalt ferrite ferromagnet is found to lead to a shift of the magnetic phase transition temperature to lower temperatures by 49 K and to a decrease in the specific heat in a wide temperature range. It is noted that the additional component of the specific heat is due to transitions of cobalt or iron ions to higher energy levels and also due to a distortion of the lattice parameters as a result of formation of three coexisting phases.