Search

Barium titanate ceramics doped with yttrium as well as silica and alumina have been studied with special reference to the effects of the yttrium content. An yttrium content at which the ceramics showed a minimum resistivity increased with the increase of the sintering temperature and the added amounts of SiO2Al2O3. The microstructural studies with the electron probe X-ray microanalyzer revealed that these results should be explained in terms of the grain growth inhibitor effects of yttrium and the segregation of it to grain boundaries.

Ferroelectric PZT films were successfully fabricated by reactive magnetron sputtering using a composit metal target. The films often showed asymmetric hysteresis loops which were brought about by a spontaneous internal biasing field. The field also affected stability of the poled film during application of a high ac voltage. In some cases, films without poling treatment showed evident pyroelectric response.

The paper describes a loop tracer for observing hysteresis phenomena in ferroelectrics; the tracer utilizes recent digital technology and can record the hysteresis phenomena instantaneously. As the operation speed is very fast, it is easy to observe the loop of aged specimens without changing their electrical state, as well as to trace the depolarizing process dynamically when an ac voltage is applied. From the data obtained a new representation for ferroelectric hysteresis curve has been proposed and discussed with special reference to determination of an internal bias field in the materials.