Aging inK1−xLixTaO3: A Domain Growth Interpretation

The aging behavior of the ac susceptibility of randomly substituted ${\mathrm{K}}_{1-x}{\mathrm{Li}}_x{\mathrm{TaO}}_3$ crystals reveals marked differences with spin glasses in that cooling rate effects are very important. The response to temperature steps (including temperature cycles) was carefully studied. A model based on thermally activated domain growth accounts for all the experimental results, provided one allows for a large distribution of pinning energies, in such a way that “slow” and “fast” domains coexist. Interesting similarities with deeply supercooled liquids are underlined.