Effect of low-angle boundaries on the dielectric properties of epitaxial Ba0.8Sr0.2TiO3 films

The effect of low-angle boundaries on the dielectric properties of epitaxial Ba 0.8 Sr 0.2 TiO 3 films is studied by comparing films differing in crystalline-block size. It is found that the permittivity diminishes considerably when the block sizes are reduced. The maximum of the temperature-dependent permittivity is shifted towards lower temperatures, and the sensitivity of the permittivity to an electric field is reduced. Moreover, it is found that the maximum in the permittivity temperature dependence is displaced towards lower temperatures when the applied measured voltage is increased and becomes higher than the coercive voltage. The width of a hysteresis loop decreases significantly when the frequency of the controlling field is reduced. The reasons for the observed behavior are analyzed.