Internal Stress Effect on the Temperature Dependence of the Dielectric and Lattice Constant in Sm-doped BaTiO3 Ceramics

概要

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The internal stress effect on the temperature dependence of the dielectric and lattice constant in a Sm-doped BaTiO3 ceramic was investigated using various particle sizes of starting barium titanate, pressure-dielectric spectroscopy and a high pressure X-ray diffractometer. The grain size was nearly proportional to the particle size of the starting barium titanate, while inversely proportional to the internal stress. A sudden change of internal stress occurred at a grain size of ≈2 µ m. Grain size refinement, as well as external pressure, shifts the lattice and dielectric anomaly T c to a lower temperature, whereas T2 is shifted to a higher temperature. For ceramics with a grain size of 2.6 µ m, T1 decreases with increase in pressure, reaches a minimum value at 5 kbar and then increases. Three lattice anomalies existed for small grained ceramics (<2 µ m) irrespective of grain size and at pressures up to 100 kbar. In particular, the temperature dependence of the dielectric and lattice constant for small grained ceramics (<2 µ m) was less sensitive to external pressure in comparison to that of large grained ceramics (>2 µ m), which was attributable to the internal stress (>240 MPa).
INSTITUTE OF PURE AND APPLIED PHYSICSの論文
1997-06-15