Non-phonon contribution to the specific heat of PbMg1/3Nb2/3O3 at low temperatures

Measurements of specific heat of relaxor ferroelectric PbMg1/3Nb2/3O3 (PMN) in the temperature range from 2 to 300 K by adiabatic calorimetry and rela xation technique are reported. Comparison of different approaches to descri ption of the temperature dependence of specific heat has shown that experim ental data can be adequately described in terms of fractal formalism, Spect ral dimension inferred from low temperature specific heat measurements was found to be in good agreement with spectral dimension estimated from inelas tic neutron scattering data. (C) 2001 Elsevier Science B.V. All rights rese rved.