This work reports the effect of lithium doping on the dielectric and polar properties of potassium tantalate. Experimental data were obtained in K 1−x Li x TaO 3 ceramics with x = 0, 0.02, 0.05 and 0.10 by measuring both the dielectric permittivity from 10 2 to 10 8 Hz, and polarization under an ac electric field driven at 2.5 Hz, for temperatures from 10 to 300 K. The dielectric permittivity exhibits all the relaxations reported for K 1−x Li x TaO 3 single crystals. Two dielectric relaxations

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... bserved at 40-125 K are ascribed to the individual hopping by 90 • and 180 • of dipoles created by the off-centre Li ions. Another relaxation observed at 100-200 K is related to 180 • -flips of Li pairs for x = 0.02 and of polar clusters of interacting Li ions for x = 0.05 and 0.10. In addition to that, an additional relaxation not reported before is presented at 135-235 K for x = 0.10 and attributed to 90 • -reorientation of Li polar clusters. Both the change from an Arrhenius to a Vogel-Fulcher dependence with increasing lithium content, and the emergence of slim P (E) hysteresis loops around the relaxation temperatures show that the relaxation dynamics in K 1−x Li x TaO 3 can be understood if a crossover from a dipolar glass to a relaxor-like behaviour is assumed.