IMF2017

Structural and electrical properties of Ba[(Ga,Ta)_0.05Ti_0.9]O_3­ and Ba_0.8Sr_0.2[(Ga_0.05,Ta_0.05)Ti_0.9]O₃ have been characterized to determine the effects of charge compensated dipole pairs (Ga⁺³_, Ta⁺⁵) on temperature-dependent material properties. XRD and Rietveld analysis have been used to determine lattice parameters, phase transition temperature(s), and coefficients of thermal expansion from RT to 1000 ^oC. Capacitance measurements have been conducted over the temperature range -180 ^oC to 200 ^oC and frequency range 100 Hz to 1 MHz to investigate the dielectric properties, including Curie temperature. Ba[(Ga,Ta)_0.05Ti_0.9]O₃ has a maxima in the relative permittivity curve that correspond to the tetragonal to cubic phase transition which is consistent with the Rietveld refinement of XRD data. The ɛ_r value for Ba[(Ga_0.05,Ta_0.05)Ti_0.9]O₃ is 600 at 100^oC and varies by ~ 25% over the temperature range [RT, 170]. Sr substitution for Ba in the A-site of dipole pair substituted ABO₃ is used to investigate the possibility of further increasing the relative permittivity value while maintaining the same trend of temperature insensitivity of relative permittivity. Experimental results are compared with several currently utilized models in an effort to better understand the effect of randomly dispersed charge compensated dipole pairs have on temperature-dependent material properties.