EFFECT OF SR2+ SUBSTITUTION ON DIELECTRIC PROPERTIES AND PTCR BEHAVIOR OF BATIO3
Keywords:
BaTiO3, dielectric, positive temperature coefficient resistivity, PTCRAbstract
Ba1-xSrxTiO3 ceramics have been widely used as electronic materials. However, conflicting results forthe effect of Sr2+ for the maximum value of the relative dielectric constant at the Curie point ofBa1-xSrxTiO3 ceramics have been reported. Several researchers have studied the possibility of usingBa1-xSrxTiO3 ceramics as positive temperature coefficient resistivity (PTCR) material but completeinformation has not been fulfilled. The purposes of this study were to the ascertain the effect of Sr2+substitution on some dielectric and electrical properties of BaTiO3 and to further investigate thepossibility of utilizing Ba1-xSrxTiO3 ceramics as PTCR materials. In this study an X-ray diffractometerand scanning microscope were used to study phases and microstructures of Ba1-xSrxTiO3. In addition,the capacitance and resistance of Ba1-xSrxTiO3 were measured and their relative permittivity andresistivity were calculated and analyzed. Results indicated that Sr2+ substitutions cause the unit cell ofBa1-xSrxTiO3 to shrink and change from a tetragonal to a cubic symmetry. Moreover, Sr2+ substitutionshifts the Curie point of Ba1-xSrxTiO3 to a lower temperature. Lastly, pure Ba1-xSrxTiO3 does not displaygood PTCR characteristics for commercial PTCR material.
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