The effect of low Sn doping on the dielectric and electrocaloric properties of ferroelectric ceramics Ba 0.95 Sr 0.05 Ti 0.95 Zr 0.05 O 3 (original) (raw)
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Materials Science and Engineering: B, 2010
Lead-free Ba 0.7 Ca 0.3 Ti 1-x Sn x O 3 (x = 0.00, 0.025, 0.050, 0.075, and 0.1, abbreviated as BCST) electroceramic system was prepared by solid state reaction method and investigated its ferroelectric, piezoelectric and electrostrictive properties. X-ray diffraction shows that the compositions with x ≤ 0.05 exhibit a tetragonal crystal structure having P4mm symmetry; while the compositions x = 0.075 and 0.1 exhibit a mixed P4mm + Amm2 phase coexistence of tetragonal and orthorhombic and P4mm + Pm m pseudo-cubic lattice symmetries, respectively at room temperature. The dense microstructure having relative density ~90-92% and average grain size in the range ~2.36 µm to 8.56 µm was observed for BCST ceramics. Temperature dependent dielectric measurements support the presence of phase coexistence Accepted Article This article is protected by copyright. All rights reserved. and show the decrease in Curie temperature (T C) with Sn 4+ substitution. The dielectric loss (tan δ) values in the temperature range (-100 ᵒC to 150 ᵒC) was observed to be less than 4%, for all BCST ceramics. The BCST compositions exhibit typical polarization-electric field (P-E) hysteresis and electric field induced strain (S-E) butterfly loop, which confirms the ferroelectric and piezoelectric character. The compositions x = 0.025, 0.05 and 0.075 show the peaking behavior of displacement current density () to an applied electric field () (J-E) which implies the saturation state of polarization. The maximum electrostrictive coefficient (Q 33) value of 0.0667 m 4 /C 2 was observed for x = 0.075 and it is higher than some of the significant lead based electrostrictive materials. The compositions x = 0.05 and 0.075 exhibit the notable electrostrictive properties that may be useful for piezoelectric Ac device applications. The observed results are discussed and correlated with the structure-propertycomposition.
2019
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 950C have well crystallized into perovskite structure suggesting the substitution of Ti4+ by Sn4+ 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 = 20C 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 DTEC = 0.188 K at an applied electric field of only 7 kV/cm. Impedance spectrum analysis of all the samples performed in th...
Journal of Materials Science: Materials in Electronics
Ferroelectric ceramics (Ba 0.85 Ca 0.15)(Ti 0.9 Zr 0.1-x Sn x)O 3 (x=0.00, 0.02, 0.04, 0.06) were prepared by a sol-gel method. Structural investigation revealed the coexistence 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 Sn 4+ 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.
Investigation of Dielectric and Ferroelectric Properties of the Pb(Sn,Zr,Ti)O 3 Ceramics
Ferroelectrics, 2004
Dielectric and ferroelectric properties of ceramic solid solutions (Pb 0.98-x Ba x La 0.02) (Sn 0.35 Zr 0.55 Ti 0.10)O 3 (I) and (Pb 0.98-x Ba x)(Sn 0.35 Zr 0.55 Ti 0.10 Nb 0.02) 0.995 O 3 (II), x = 0.09-0.13 have been studied. It was found out that ferroelectric properties are promoted by addition of Nb cations. With increasing x relaxor behavior becomes evident in the both systems.
Dielectric and ferroelectric properties of Ba 0.8Sr 0.2Ti 1−5 x/4 Nb x O 3 ceramics
Thin Solid Films, 2011
Multilayered BaTi 1-x Sn x O 3 (BTS) ceramics with different Ti/Sn ratios were produced by pressing and sintering at 1420 o C for 2 hours. X-ray diffractometry, scanning electron microscopy and energy dispersive spectroscopy were used for structural, microstructural and elemental analysis, respectively. The dielectric and ferroelectric behavior of sintered samples was studied, too. It is found that in ingredient materials, with increasing Sn content, the tetragonality decreases; Curie temperature moves towards room temperature, while the maximum of the dielectric constant increases, and also, they becomes less hysteretic. It is noticed that multilayered BTS ceramics with different Ti/Sn contents have a broad transition temperature and show a relatively high dielectric constant in a wide temperature range. It is shown that dielectric properties of these materials may be modified by a combination of different BTS powders as well as layers number.
2021
We have studied the effects of Zn and Nb substitutions on dielectric, ferroelectric, and piezoelectric properties of Ba0.87Ca0.13(Ti0.9Zr0.1)(1−x)(Zn1/3Nb2/3)xO3 ceramics. X-ray diffraction (XRD) results display that morphotropic boundary occurs from tetragonal to orthorhombic region for x = 0; 0.005; 0.01 and polymorphic phase transitions from tetragonal to orthorhombic and rhombohedral regions for x = 0.02. The evolution of the Raman spectra demonstrates the introduction of a disorder in this composition, which promotes ferroelectric relaxor behaviors. Ferroelectricity is confirmed by hysteresis investigation. A piezoelectric coefficient of d33 = 205 pC N−1 and a high planar electromechanical coupling factor of kp = 47% are reported for x = 0.1. The ceramics for x = 0.01 also depicts uniform microstructure that contributes to the important electrical properties. These results indicate that this Ba0.87Ca0.13(Ti0.9Zr0.1)(1−x)(Zn1/3Nb2/3)xO3 system with optimal composition is a promi...
Dielectric and Ferroelectric Properties of Lead-Free Ceramic System
Advances in Materials Science and Engineering, 2013
Lead-free specimens of [1 − {(Bi 1− La ) 0.5 (Na 1− Li ) 0.5 TiO 3 }-BaTiO 3 ] (BLNLT-BT, where = 0.04, = 0.025, and = 0, 0.02, 0.04, and 0.06) ceramic system were synthesized by a semiwet technique. In the present study, we have investigated the effect of Ba on the structure, morphology, and dielectric, ferroelectric, and piezoelectric properties of BLNLT system. The XRD patterns of all the specimens showed rhombohedral structure at room temperature. Field emission scanning electron microscopy images (FE-SEM) showed grain growth inhibition with Ba content in BLNLT system. The temperature dependence of dielectric constant revealed that the temperature of maximum dielectric constant " " and depolarization temperature " " decreased for the sample = 0.06 and showed high value of dielectric constant with low dielectric loss. These samples exhibited nonlinear behaviour of hysteresis loop. The values of dielectric constant ( ), dissipation factor (tan ), piezo charge coefficient ( 33 ), remnant polarization ( ), and coercive field ( ) for the composition = 0.06 were 1495, 0.06, 20 pC/N, 5 C/cm 2 , and 10.5 kV/cm, respectively.