The investigation of piezoelectric features of lead-free barium titanate ceramic materials at different initial temperatures in the tetragonal phase using molecular dynamics simulation

This study used molecular dynamics simulation to investigate how temperature changes the piezoelectric properties of crystal barium titanate in its tetragonal form. Consistent with the results, the oxygen diffusion coefficient in the simulated sample increased to 0.35 Å2/ns (expansion mode) and 0.56 Å2/ns (contraction mode) by increasing the temperature from 300 to 400 K. Moreover, the piezoelectric coefficient of samples decreased from 267.22 to 162.56 in an expansion mode and from 189.96 to 145.21 in a contraction mode by increasing temperature. On the other hand, increasing the temperature decreased saturation polarization (from 0.372 to 0.290 C/m2), coercivity field (from 0.259 to 0.155 MV/m), and residual polarization (from 0.154 to 0.084). This decrease may be due to approaching the critical temperature and changing the structure from tetragonal to cubic. Finally, the results show that the dielectric coefficients were found by raising the temperatures to 400 K (expansion mode) and getting 73, 70, 68, and 64. For the contraction mode, they were 70, 66, 55, and 63.