Pb5Ge3O11 ferroelectric films prepared by a modified sol-gel method

Single-crystal Pb5Ge3O11 films 5-105 mu m thick, adhering well to platinum substrates, were prepared by pyrolysis of metalorganic precursors in combin ation with in situ sol-gel processing. The best films consisted of densely packed crystallites ranging in size from 200 to 300 mu m, with hexagonal ha bits. A well-defined ferroelectric transition was revealed at 170-180 degre es C. The typical parameters of the films are epsilon(20) = 30-40, tan delt a congruent to 0.02, epsilon(max) congruent to 200, P-s = 3.2 mu C/cm(2), E -c = 16 kV/cm, and rho = 10(8)-10(9) Omega cm, in agreement (except for eps ilon(max)) with those of lead germanate crystals.