Domain-wall freezing in Cd2Nb2O7 pyrochlore single crystal

Cadmium niobate Cd2Nb2O7 is a rare example of a bulk ferroelectric with a pyrochlore structure, which is characterized by an extremely complex phase diagram and contradictions in the structural phase transitions and polar states. Here, the dielectric spectroscopy studies of the Cd2Nb2O7 single crystals were performed. For the first time it was shown that dielectric behavior of these crystals demonstrates all typical features of the domainwall "freezing" dynamics such as the characteristic "kink" on the temperature dependence of the real part of the dielectric permittivity as well as the fulfillment of the Vogel-Tammann-Fulcher relation of the experimentally determined temperature dependence of the relaxation time. It was found that the contribution of the domainwall relaxation process to the total low-frequency dielectric permittivity is more than 85% at the temperature at which the dielectric dispersion is most pronounced. Thus, a limited family of the ferroelectrics exhibiting domain-wall freezing phenomena was expanded.