“…In these materials low frequency dielectric hysteresis loops were obtained from the measurements of the capacity dependence on the applied voltage. 13,14 Nowadays such typical ferroelectric semiconductors such as BaTiO 3 ceramics, disordered and relaxor SBN-x, PbZr x Ti 1−x O 3 ͓PZT͑x /1−x͔͒ solid solutions slightly doped with Fe, Cr or La, Nb, Nd, Ce, etc., their films, multilayers, and heterostructures are widely used in sensors, actuators, electro-optic, piezoelectric, and pyroelectric devices, and memory elements. 13 Pyroelectric loops usually are sloped and slim; no maxima of pyroelectric response near the coercive field are observed.…”