Specific heat and heat conductivity of BaTiO3polycrystalline films in the thickness range 20–1100 nm

Abstract

Thermal properties - specific heat and heat conductivity coefficient—of polycrystalline BaTiO3films on massive substrates were studied as a function of the temperature and thefilm thickness by the ac-hot probe method. The anomalies of specific heat withthe film thickness decreasing from 1100 to 20 nm revealed the reduction ofTcand excess entropy of the ferroelectric phase transition whichbecomes diffused. The critical thickness of the film at whichTc = 0has been estimated as 2.5 nm.