Phase Transitions and Electrocaloric Effect in Ca-Modified Na1/2Bi1/2TiO3–SrTiO3–PbTiO3 Solid Solutions

The electrocaloric effect as a function of Ca concentration is studied in 0.4Na
_1/2
Bi
_1/2
TiO
₃
-(0.4-x)SrTiO
₃
-0.2PbTiO
₃
-xCaTiO
₃
. Weak influence of Ca at low concentrations corresponds to the previously established concentration dependence of phase transition temperature and polarization, whereas the decrease of electrocaloric effect at phase transition at higher concentrations of Ca can be explained by assuming increasing concentration of polar nanoregions. The role of thermal depoling in the case of electric-field-induced phase transition is shown.