Electric Field Dependent Specific Heat of SrTiO 3 , BaTiO 3 and KTaO 3 Ferroelectric Perovskites

The field dependent specific heat of anharmonic ABO3 type displacive ferroelectrics (SrTiO3, BaTiO3 & KTaO3) is studied using double time Green’s function technique along with Silverman-Joseph modified Hamiltonian which includes anharmonicity up to the fourth order due to the interaction of the soft mode. The soft mode contributions to specific heat are described by appropriate Einstein terms. The variation of specific heat with temperature and electric field is discussed. The specific heat in all three crystals increases non-linearly with temperature. The specific heat decreases with increase in external electric field. The effect of electric field on specific heat is more prominent in low temperature sides in all three crystals. The effect of temperature reduces in low field region and the change in specific heat arises mainly due to higher order anharmonic terms. The results are in agreement with previous experimental and theoretical results.