  Ferroelectric ceramics (Ba0.85Ca0.15)(Ti0.9Zr0.1-xSnx)O3 (x=0.00, 0.02, 0.04,
0.06) were prepared by a sol-gel method. Structural investigation revealed the
co-existence of tetragonal (P4mm) and orthorhombic (Pmm2) symmetries at room
temperature for the undoped ceramic, while only a tetragonal structure (P4mm)
was observed for the doped ceramics. Dielectric measurements indicate a
dielectric relaxation process at high temperatures which is essentially related
to the hopping of oxygen vacancies. Furthermore, a down shifting of the Curie
temperature (TC) with increasing Sn4+ doping rate has been revealed. The
temperature profiles of the Raman spectra unveiled the existence of polar
nanoregions (PNRs) above the Curie temperature in all ceramics. The
ferroelectric properties were found to be related to the microstructure.
Electrocaloric effect was investigated in this system that revealed an
electrocaloric responsivity of 0.225 10-6 K m/V for the composition with x =
0.04 Sn doping, where other remarkable physical properties were also observed.
