Dielectric, ferroelectric and electrocaloric properties of 1%Eu - doped BaZryTi1-yO3 ceramics

Pure perovskite 1%Eu - BaZrTiO ceramics with compositions y = 0, 0.05, 0.15, and 0.30 prepared by solid-state reaction were investigated by impedance spectroscopy and high field measurements (P(E), dc-tunability). The ceramic samples present a nonlinear dielectric character and the dc-tunability reaches a maximum for y = 0.15 (n = 85%) due to the proximity of the ferroelectric-paraelectric phase transition and due to a good accommodation of the europium ions into the BZT matrix. All the compositions have a maximum temperature change around the phase transition with a maximum ?T=1.13 K for y = 0. At room temperature, the maximum is found for the composition y = 0.05 (?T=0.46 K), while for y = 0.15 a constant value ?T=0.40 K was obtained from room temperature up to 350 K. This kind of electrocaloric dependence, the large nonlinear dielectric character with the lack of hysteresis in the permittivity vs. field dependence make this composition as interesting for microelectronics applications.