Structural, dielectric and electrocaloric properties of (Ba0.85Ca0.15)(Ti0.9Zr0.1-xSnx)O-3 ceramics elaborated by sol-gel method

S. Belkhadir , A. Neqali (1) , M. Amjoud (1) , D. Mezzane (1) , A. Alimoussa (2) , E. Choukri (1) , Y. Gagou (3) , I Raevski , M. El Marssi (3) , Igor A. Luk'Yanchuk (3) , B. Rozic , Z. Kutnjak (4)

1 LMCN - Laboratoire de Matière Condensée et Nanostructures
2 Laboratory of Condensed Matter and Nanostructures
3 LPMC - Laboratoire de Physique de la Matière Condensée - UR UPJV 2081
4 IJS - Jozef Stefan Institute [Ljubljana]

Ferroelectric ceramics (Ba0.85Ca0.15)(Ti0.9Zr0.1-xSnx)O-3 (x = 0.00, 0.02, 0.04, 0.06) were elaborated by sol-gel method. Structural investigation revealed 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 (T-C) with increasing Sn4+ doping rate has been revealed. The temperature profiles of the Raman spectra unveiled the existence of polar nanoregions 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 x 10(-6) K m/V for the composition with x = 0.04 Sn doping, where other remarkable physical properties were also observed.

Domaines: Matière Condensée [cond-mat]

S. Belkhadir, A. Neqali, M. Amjoud, D. Mezzane, A. Alimoussa, et al.. Structural, dielectric and electrocaloric properties of (Ba0.85Ca0.15)(Ti0.9Zr0.1-xSnx)O-3 ceramics elaborated by sol-gel method. Journal of Materials Science: Materials in Electronics, 2019, 30 (15), pp.14099-14111. ⟨10.1007/s10854-019-01776-1⟩. ⟨hal-03627565⟩