Impedance spectroscopy analysis of pure and Ni-doped lithium tantalate

Ceramics of LiTaO3 with different Li/Ta ratios and Li0.98-x Ta1.004-x 5NixO 3 solid solutions with 0 less than or equal tox less than or equal to0.20 a re studied by impedance spectroscopy in the 1 Hz-1 MHz frequency range and the 500-1200 K temperature range. The evolution of the dielectric propertie s and the Curie temperature are studied as a function of the Li/Ta ratio an d of the Ni content. The ionic conductivity is determined for all compositi ons from Cole-Cole diagrams and the evolution vs temperature is studied as a function of the Li/Ta ratio and of the Ni content. The results are discus sed and related to the substitution mechanism. (C) 2001 Elsevier Science Lt d. All rights reserved.