Energy Loss Processes in Ferroelectric Ceramics

By a study of ageing effects in which permittivity, elastic compliance and the electrical and mechanical loss coefficients decrease with time, the principal ferroelectric loss process in low fields is identified as microhysteresis associated with small-amplitude domain boundary movement. Larger fields produce macrohysteresis effects due to large-scale boundary movement, and the permittivity, compliance and loss coefficients are increased. Although boundary movement is responsible for almost all the energy loss, its contribution to permittivity and compliance is usually small compared with induced effects within each domain. Thus a change in the magnitude of boundary movement alters the permittivity and compliance only slightly, but changes the loss coefficients considerably.