Dielectric investigation of alpha-LiIO3

The dieiectric properties of hexagonal lithium iodate (alpha-LiIO3) single crystals have been studied at frequencies 10(-2) Hz less than or equal to v less than or equal to 10(9) Hz and temperatures 100 K less than or equal to T less than or equal to 500 K. Pure and iron doped crystals were investigated. Below approximately 10 kHz, the electric response of the LiIO3 crystals is almost entirely dominated by the accumulation of space charges at the electrodes. At least two types of ionic charge carriers seem to contribute to the observed conductivity. In addition, de measurements revealed that electronic conductivity cannot be neglected in alpha-LiIO3. At frequencies above some 100 kHz the real part of the conductivity follows a power law sigma'similar to nu(s) with relatively small exponents s for both, the doped and the undoped compounds. The temperature dependence of d in this region behaves thermally activated with two energy barriers. The high-frequency limit of the dielectric constant epsilon(infinity) has been determined. In addition, the data have been evaluated using the modulus formalism.