DIELECTRIC RESPONSE OF LI0.4K0.6NBO3 CRYSTAL IN THE FREQUENCY-DOMAIN

Complex impedance and dielectric constants of ferroelectric crystals L i0.4K0.6NbO3 have been studied in the frequency domain at several temp eratures. A strong low-frequency dielectric dispersion below 1 kHz was revealed in the high temperature range. The normalized behaviour of t he complex dielectric constants satisfies the universal dynamic respon se with its power exponent n=0.04. In the high frequency region, the c omplex impedance was described by a modified Cole-Cole arc. An equival ent circuit for the transport process of high frequency region has bee n examined. The temperature-dependent exponent has its minimum at the ferro- to para-electric phase transition point and relaxation frequenc ies do not satisfy the Arrhenius law in the ferroelectric region