Microstructures and properties of semi-conductive Pb0.6Sr0.4TiO3 ceramics using PbTiO3-coated SrTiO3 powders

Microstructures and properties of semi-conductive Pb0.6Sr0.4TiO3 ceramics fabricated from PbTiO3-coated SrTiO3 powders were investigated using X-ray and electron diffraction, transmission electron microscopy and energy dispersive spectroscopy. PbTiO3-coated SrTiO3 powders were prepared for simulating the core-shell structure in Pb0.6Sr0.4TiO3 ceramics, which were sintered by microwave, rapid thermal and conventional sintering processes. After TEM investigations and EDS analyses, it is found that the microwave-sintered specimens preserve the starting core-shell structure more effectively than the conventional and rapid thermal sintered specimens. According to our core-shell model, the microwave-sintered specimens show single Tc and the conventional, rapid thermal sintered specimens exhibit double Tc behavior, as verified by the resistivity–temperature (ρ–T) properties. Our interpretation implies that the core-shell structure may be the primary factor affecting the ρ–T properties.