Electro-caloric effect in lead-free Sn doped BaTiO3 ceramics at room temperature and low applied fields

Abstract

Structural, dielectric, ferroelectric (FE), 119Sn Mössbauer, and specific heat measurements of polycrystalline BaTi1–xSnxO3 (x = 0% to 15%) ceramics are reported. Phase purity and homogeneous phase formation with Sn doping is confirmed from x-ray diffraction and 119Sn Mössbauer measurements. With Sn doping, the microstructure is found to change significantly. Better ferroelectric properties at room temperature, i.e., increased remnant polarization (38% more) and very low field switchability (225% less) are observed for x = 5% sample as compared to other samples and the results are explained in terms of grain size effects. With Sn doping, merging of all the phase transitions into a single one is observed for x ≥ 10% and for x = 5%, the tetragonal to orthorhombic transition temperature is found close to room temperature. As a consequence better electro-caloric effects are observed for x = 5% sample and therefore is expected to satisfy the requirements for non-toxic, low energy (field) and room temperature based applications.

Electrocaloric response near room temperature in Zr- and Sn-doped BaTiO 3 systems

“…an ICP [11,13]. The dielectric peaks shift to higher temperatures with an increasing BST11 ratio, because BST11 has a higher phase transition temperature (42 • C) than that of BZT18 (35 • C) [9,13,14].…”

“…In addition, the ECE was investigated in Sn-doped BaTiO 3 ceramics using the indirect method, e.g. deducing the ECE from the pyroelectric coefficient using the Maxwell relation [6,[10][11][12]. A significantly higher ECE was observed in samples with compositions at the ICP [10][11][12].…”

Electrocaloric enhancement near the morphotropic phase boundary in lead-free NBT-KBT ceramics

“…Some of the highest ECE performances ever reported were found in the Pb-containing compounds close to their MPB, such as PMN-30PT. 4 The ECE of some lead-free materials with compositions near the CP, such as Zr-doped Ba 0.8 Ca 0.2 TiO 3 , 13 Sn-doped BT, 14 or Sr-doped NBT-BT, 15,16 has also been reported, but very few were studied by direct ECE measurements.…”

Reduced leakage current and improved ferroelectricity in magneto-electric composite ceramics prepared with microwave assisted radiant hybrid sintering

“…19 Therefore, the peak at T 2 is attributed to the NZFO phase. The 5% Sn doped BaTiO 3 (BTSO) that is used as FE component in the present work shows three phase transitions i.e., cubic to tetragonal (T C−T ) at 360 K, tetragonal to orthorhombic (T T −O ) at 296 K and rhombohedral to orthorhombic (T O−R ) 246 K. 12 Unlike pure BTSO, the composite samples in the present work show broad transitions and also the T C is observed to be shifted to slightly higher temperatures. Such broadening of transition and shifting of T C is reported in similar composite samples and explained in terms of local formation of solid-solutions particularly at the grain boundaries.…”