Fracton contribution to the specific heat of the PbMg1/3Nb2/3O8 relaxor ferroelectric at low temperatures

The specific heat of the PbMg1/3Nb2/3O3 relaxor ferroelectric has been measured by the adiabatic calorimetry and the relaxation method in the temperature range 2–300 K. The low-temperature heat capacity data are compared with the experimental data on inelastic neutron scattering and discussed in the context of the present-day concepts. The analysis of various approaches to the description of the temperature dependence of the heat capacity showed that the experiment can be adequately described only within the framework of the fractal concept. The calculated value of the spectral dimension \(\tilde d = 1.6\) is consistent with the inelastic neutron-scattering data.