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RESEARCH PRODUCT

Heterogeneous and Homogeneous Diffusivity in an Ion-Conducting Glass

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description

The nature of ion diffusivity in the vitreous conductor 2Ca NO3 2 ? 3KNO3 (CKN) was studied by nonresonant dielectric hole burning. Spectral holes in the electric field relaxation are probed subsequent to a high electric sinusoidal burn field. For sufficiently high pump frequencies we are able to induce spectrally selective modifications in the relaxation of the electric modulus, indicating that ionic diffusivity is a spatially varying quantity in glassy CKN. Homogeneous behavior occurs in the regime of low pump frequencies, in which the resistivity approaches its steady state value. Thus, longer-ranged ionic motions lead to a spatial averaging over the heterogeneity of local ion diffusivities.