Equal-permittivity states induced in a ferroelectric

Conditions under which a ferroelectric subjected to an electric field acquires equal-permittivity paraelectric states at different temperatures are studied. The temperature dependences of the control (inducing) field intensity and feasible permittivity interval (epsilon(min)-epsilon(max)) are obtained. The effect of intersection of the epsilon(E, T-i) characteristics of the ferroelectric in the paraelectric state is analyzed. With the control field and temperature varying consistently, the permittivity epsilon(i) of strontium titanate films and films of the barium titanate-strontium titanate solid solution may be kept constant in a wide (200-320 K) temperature range and, at the same time, changed by more than twofold by varying the electric field. (C) 2004 MAIK "Nauka / Interperiodica".