  Ba{[Gax,Tax]Ti(1-2x)}O3 ceramics with x equal to 0, 0.0025, 0.005, 0.01,
0.025 and 0.05 have been prepared by conventional solid-state reaction.
Structural and dielectric characterization have been performed to investigate
the effect of dipole-pair substitution concentration on the macroscopic
dielectric properties. Ba{[Gax,Tax]Ti(1-2x)}O3 evolves from a classic
ferroelectric to a diffuse phase transition (DPT) as x increases.
Ba{[Gax,Tax]Ti(1-2x)}O3 for x > or = 0.01 possesses diffuseness parameters
comparable to Pb(Mg1/3Nb2/3)O3-PbTiO3 (PMN-PT) and recently reported
(Ba0.97Pr0.03)(Ti0.9425Ce0.05)O3 (BPTC), yet it lacks the frequency and
temperature dependence of Tm necessary to be a strictly defined relaxor
ferroelectric. Additionally, Ba{[Ga0.05,Ta0.05]Ti0.9}O3 possesses a relative
permittivity, {\epsilon}r, of 700+/-16% and dissipation factor less than 0.05
at 10 kHz within the temperature range [-75{\deg}C, 120{\deg}C]. In comparison
to BaTiO3, Ba{[Gax,Tax]Ti(1-2x)}O3 possesses enhanced electrical resistivity at
and above room temperature. In-situ XRD, including Rietveld refinement, have
been performed to determine the lattice parameter, coefficient of thermal
expansion and phase transition temperature (Tc) of each composition within the
temperature range [RT, 1000{\deg}C], thus linking the dielectric properties
with the materials structure. These studies have been corroborated by
temperature dependent Raman spectroscopy to compare the Tc determined by
electrical and structural characterization. The properties of
Ba{[Gax,Tax]Ti(1-2x)}O3 are discussed in context with available models that
describe donor and acceptor dopants spatially separated in the parent matrix,
inter-relating lattice parameter, Curie temperature, and other material
properties
