Low-temperature specific heat in ferroelectric (Pb,Ba)5Ge3O11 crystals

We report specific-heat measurements in ferroelectric (Pb1-xBax)5Ge3O11 single crystals for x=0 and 0.02, from 2 80 K. We consider the data in terms of a classical Debye model, and allow for the possibility of an extra low-temperature term CLT and an extra high-temperature Einstein term CE (to account for extra oscillators). The data are accounted for with just the Debye model; CLT and CE terms are not needed, and the implications of these results are discussed. © 1988 The American Physical Society.