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The effect of fatigue on the electrical properties of sol-gel derived ferroelectric barium titanate (BaTiO3) thin films have been investigated. At room temperature, the resistivity, breakdown field, dielectric constant (ε), and loss tangent (tan δ) decreases after fatigue while the coercive field increases. Fatigue also influences the dielectric properties of the film at high temperatures. The sharpness and magnitude of the peak in the dielectric constant at the transition temperature decreases after fatigue. The loss tangent of the virgin film showed a peak at the transition temperature while it is absent in the case of the fatigue film. The phenomena are explained in terms of (i) the accumulation of point charge defect, (ii) the pinning of domain wall mobility, and (iii) the space charge layer models of fatigue.

The lattice constant, dc resistivity, dielectric constant, saturation magnetization and Curie temperature were studied on a series of Cr-substituted Li-Sb ferrite systems. The dc resistivity increases with increase of the chromium level. A change in slope was observed in the variation of resistivity with temperature and hence two regions of different activation energy. The study of dielectric permittivity with frequency showed dispersion for the whole system. The saturation magnetization and the Curie temperature were found to decrease with increase of the substitution level.

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