Study on curie temperature mechanism and electrical properties of BiFeO3-doped (Ba,Ca) (Ti,Sn)O3 ceramics

In this study, we investigated the phase structure, Curie temperature, dielectric properties, piezoelectricity, and energy-storage properties of BiFeO 3 (BFO)-modified (Ba 0.95 Ca 0.05 ) (Ti 0.89 Sn 0.11 )O 3 (BCTSO) ceramics using both experimental and theoretical methods. The results indicated that the lattice distortion and chaotic distribution of the local charge increased with the BFO content, resulting in a phase transition and transformation from a ferroelectric to a relaxing ferroelectric. First-principles calculations revealed that the Curie temperature decreased with increasing BFO content, primarily because of an increase in the ground state energy. The variation in the permittivity of the BCTSO- x BFO ceramics with temperature and frequency is affected by the phase structure and Maxwell-Wagner interface polarisation, respectively. The electrical modulus measurements indicated that BCTSO- x BFO exhibited non-Debye-type dielectric relaxation for x  = 0.0, 0.1, and 0.5 %, whereas BCTSO- x BFO showed Debye-type dielectric relaxation for x  = 0.9%.