Direct electrocaloric, structural, dielectric, and electric properties of lead-free ferroelectric material Ba0.9Sr0.1Ti1-xSnxO3 synthesized by semi-wet method

Abstract

By using the semi-wet synthesis method, lead-free ferroelectric materials Ba0.9Sr0.1Ti1-xSnxO3 with x = 0, 0.02, 0.05, and 0.10 (abbreviated as BSTS) were prepared and their structural, electric and electrocaloric properties were investigated. The X-ray diffraction (XRD) patterns show that the samples calcined at 950°C have well crystallized into perovskite structure suggesting the substitution of Ti 4+ by Sn 4+ in BST lattice. With increasing content of Sn, the enhancement of the dielectric permittivity was observed for (0≤x≤0.05) and the ferroelectric transition temperature (TC) was found to shift towards the room temperature (TC = 20°C for x = 0.10). Direct measurements of the electrocaloric effect (ECE) were performed on all samples by using the highresolution calorimeter. It is found that Ba0.9Sr0.1Ti0.95Sn0.05O3 exhibits a high ECE temperature change of TEC = 0.188 K at an applied electric field of only 7 kV/cm. Impedance spectrum analysis of all the samples performed in the temperature range of 300-360°C reveals the existence of two relaxation contributions related to the grain and grain boundaries that are well separated in frequency. Activation energies of conduction and relaxation processes were deduced for both contributions in order to determine the conduction mechanism of the studied compositions.2

Structural, dielectric, ferroelectric and tuning properties of Pb-free ferroelectric Ba0.9Sr0.1Ti1-xSnxO3

“…1(b) is consistent with the coexistence of structural phases in intermediate compositions from tetragonal to cubic phases. Moreover in Fig.1(b), it can be seen that in BSTS-x ceramics with x = 0.00 and 0.02 (200) reflection peak splits into (200) and (002) peaks that are fingerprints of tetragonal (T) phase, which is similar to previous reports [13,14]. For 0.05 x  0.07, the phase structure shifts from the (T) phase to the coexistence of Orthorhombic (O) and (T) phases.…”

“…Detailed examinations of dielectric and ferroelectric properties depending on Sn amount in BTS have been investigated in the literature. However, the literature survey shows limited reports on the effect of substitution of Sn 4+ in BST host lattice [12,13].…”

Origin of large negative electrocaloric effect in antiferroelectric PbZrO3

“…The electrocaloric maxima (both negative and positive) are listed in Table S1 (Supplemental Material [8] and Refs. [9,18,[23][24][25][26][27][28][29][30][31][32][33][34][35][36][37][38][39][40][41]) and are compared to other directly measured values reported in the literature. The maximum negative electrocaloric effect in PbZrO 3 is significantly higher than any result previously reported by direct measurements.…”

Electrocaloric effect and high energy storage efficiency in lead-free Ba0.95Ca0.05Ti0.89Sn0.11O3 ceramic elaborated by sol–gel method

“…Despite their robust properties, Pb-based materials face notable global restrictions, hence why it is necessary to develop new environment-friendly materials. Barium titanate BaTiO3 (BT) is a typical alternative system that can become an important candidate for this application [5]- [7].…”

“…34. In this context, several studies highlighted the partial substitution of Ti in BaTiO3 by Sn 4+ , and its effect on the phase transition dielectric behavior and electrocaloric properties [7], [12], [13]. It is well known that pure BT shows three distinct phase transitions with increasing temperature, i.e., the rhombohedral (R3m)orthorhombic (Amm2) phase transition at TR-O = -90 °C, the orthorhombictetragonal (P4mm) phase transition(TO-T =0 °C), and the tetragonal-cubic phase transition (TC= 120 °C) [14].…”