Structural, dielectric, ferroelectric and tuning properties of Pb-free ferroelectric Ba0.9Sr0.1Ti1-xSnxO3
Introduction
During the last few decades, lead free-ferroelectric materials caught the attention of researchers resulting in numerous studies. Due to its non-toxicity, barium titanate (abbreviated BT) ceramic is an attractive candidate to replace lead-based materials. Its dielectric, phase transition temperature and ferroelectric properties can be tailored by suitable doping the perovskite structure, either in the square site (occupied by Ba) or the octahedral one (occupied by Ti). Among this family, barium strontium titanate (BST) with high dielectric constant combined with low dielectric loss attracts a particular interest for dynamic random-access memory (DRAM) applications and multilayer ceramic capacitors [[1], [2], [3], [4], [5]]. The BST system is well recognized by its strong response to the DC bias electric field. This characteristic is desirable for tunable microwave devices like phase shifters and tunable filters, etc. [[5], [6], [7]]. Moreover, the isovalent substitution of Ba2+ by Sr2+ is also known to shift the Curie temperature from high to lower temperatures only by controlling the molar fraction of Ba2+/Sr2+.
It is worth to note that the substitution of Ti4+ by Sn4+ in BT lattice (abbreviated BTS) has also been an effective way to shift the Curie temperature close to room temperature and also to induce various interesting properties in the dielectric behavior and sensor applications [[8], [9], [10]]. Besides, BTS solid solutions have attracted significant attention for their potential applications in electric-field tunable devices [11]. 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 Sn4+ in BST host lattice [12,13]. Thus, the present paper aims to examine the Ba0.9Sr0.1Ti1-xSnxO3 ceramic family by performing a complete study on its crystal structure, dielectric and ferroelectric properties, including the DC-electric field dependence of the dielectric constant. A series of Ba0.9Sr0.1Ti1-xSnxO3 ceramics, with x = 0.00, 0.02, 0.05, 0.07, 0.10 and 0.15 (denoted BSTS-x) was fabricated via the conventional solid-state reaction method. A detailed structural refinement analysis based on the Rietveld method was performed on RT x-ray (XRD) patterns. Raman spectroscopy and Scanning Electron Microscope (SEM) measurement permitted to confirm phase transitions and the symmetries. Using dielectric spectroscopy, P-E and capacitance-voltage (C–V) hysteresis measurements, we determined the value of saturated polarization and highlighted strong ferroelectric activity in this system.
Section snippets
Experimental procedure
The polycrystalline BSTS-x ceramics with (x = 0, 0.02, 0.05, 0.07, 0.10 and 0.15) were synthesized by the conventional solid-state reaction method. The basic materials are BaCO3, SrCO3, TiO2 and SnO2 powders that were weighed stoichiometrically and mixed with ethanol in an agate mortar for 2 h. The mixed powder was dried and then calcined at 1150 °C for 12 h in air. After the addition of 5 wt% polyvinyl alcohol (PVA) to the calcined powder as a binder, the powders were pressed into pellets of
X-ray diffraction analysis
RT x-ray diffraction (XRD) patterns of BSTS-x ceramics are shown in Fig. 1(a). All the patterns show reflections peaks typical to BaTiO3 perovskite structure with no traces of impurities at the limit of device sensitivity, suggesting that Sn4+ has successfully diffused into the host lattice. The enlarged (200) reflection peak in the higher Sn-amount composition, around 2θ = 45°, as shown in Fig. 1(b) is consistent with the coexistence of structural phases in intermediate compositions from
Conclusions
In the present paper, Ba0.9Sr0.1Ti1-xSnxO3 sintered ceramics were studied for different compositions (x = 0.00 to 0.15). The results show that increase of Sn-amount induces the following phase transformation: the crystal structure for x = 0.00 and x = 0.02 shows best agreement with T (P4mm) phase; for x = 0.05 and x = 0.07 the analysis showed coexistence of T (P4mm) – O (Amm2) phases, while for x = 0.10 coexistence of T (P4mm) – O (Amm2) – R (R3m) phases. The composition with x = 0.15 showed
Declaration of competing interest
The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
Acknowledgements
The authors are grateful to the financial support received from the European Community through the H2020MSCA-RISE-ENGIMA-778072 project. The support from ARRS project J1-9147, program P1-0125 and the CNRST Priority Program (PPR15/2015) is gratefully acknowledged.
References (38)
Barium strontium titanate-based perovskite materials for microwave applications
Prog. Solid State Chem.
(2007)- et al.
Preparation and dielectric properties of barium strontium titanate glass-ceramics sintered from sol – gel-derived powders
Ceram. Int.
(2004) - et al.
Nonhydrolytic sol – gel synthesis and dielectric properties of ultrafine-grained and homogenized Ba0.70Sr0.30TiO3
Ceram. Int.
(2008) - et al.
Characterization of barium strontium titanate thin films for tunable microwave and DRAM applications
Surf. Coat. Technol.
(2005) - et al.
Structural evolution and electrical characteristics of Sn-doped Ba0.8Sr0.2TiO3 ceramics
Ceram. Int.
(2017) Direct electrocaloric, structural, dielectric, and electric properties of lead-free ferroelectric material Ba0.9Sr0.1Ti1-xSnxO3 synthesized by semi-wet method
Phys. B Condens. Matter
(2019)Dielectric relaxation and predominance of NSPT and OLPT conduction processes in Ba0.9Sr0.1TiO3
Superlattices Microstruct.
(2019)Polymorphic phase transition and enhanced piezoelectric properties in (Ba0.9Ca0.1)(Ti1-xSnx)O3 lead-free ceramics
Mater. Lett.
(2013)Ferroelectricity and high tunability in novel strontium and tantalum based layered perovskite materials
J. Eur. Ceram. Soc.
(2018)- et al.
Pyroelectric properties in sol – gel derived barium strontium titanate thin films using a highly diluted precursor solution
Appl. Phys. Lett.
(2000)
Ferroelectric materials for microwave tunable applications
J. Electroceram.
Enhanced microwave dielectric properties of Ba0.4Sr0.6TiO3ceramics doping by metal Fe powders
J. Appl. Phys.
Effect of Sn doping on the phase transformation properties of ferroelectric BaTiO3
J. Mater. Sci. Mater. Electron.
Related content dielectric properties and phase transitions of Ba(Ti1-xSnx)O3 solid solution
Dielectric relaxation behavior in barium stannate titanate ferroelectric ceramics with diffused phase transition
Dielectric characteristics and tunability of barium stannate titanate ceramics
J. Electroceram.
Ferroelectric phase changes and electrocaloric effects in Ba(Zr0.1Ti0.9)1−xSnxO3 ceramics solid solution
J. Mater. Sci.
R factors in Rietveld analysis: how good is good enough?
Powder Diffr.
The effect of Sn for Ti substitution on the average and local crystal structure of BaTi1-xSnxO3 (0 ≤ x ≤ 0.20)
J. Appl. Crystallogr.
Cited by (11)
Improvement of the electrocaloric effect and energy storage performances in Pb-free ferroelectric Ba<inf>0.9</inf>Sr<inf>0.1</inf>Ti<inf>0.9</inf>Sn<inf>0.1</inf>O<inf>3</inf> ceramic near room temperature
2022, Journal of Solid State ChemistryCitation Excerpt :It is worthing to note that many researchers focus mostly on the improvement of electrocaloric temperature and/or energy storage density for bulk materials, neglecting the practical applications in room temperature. To the best of our knowledge, only a few studies have reported on the energy storage and electrocaloric properties of Ba1-xSrxTi1-ySnyO3 solid solutions, which are obtained by replacing Ba ions with Sr ions and Ti ions with Sn ions [36–38]. Indeed, our previous research [39] highlighted that the partial replacement of Sr2+and Sn4+ in BT matrix (with nominal composition Ba0.9Sr0.1Ti0.9Sn0.1O3) has shifted the ferroelectric paraelectric (FE – PE) phase transition to RT and enhanced its dielectric properties.
Enhanced electrocaloric and energy-storage properties of environment-friendly ferroelectric Ba<inf>0.9</inf>Sr<inf>0.1</inf>Ti<inf>1−x</inf>Sn<inf>x</inf>O<inf>3</inf> ceramics
2022, Materials Today CommunicationsCitation Excerpt :Thus, a part of the present paper focuses on the lead-free ferroelectric Ba0.9Sr0.1Ti1−xSnxO3 (denoted BSTS-x) ceramics as potential candidates for solid-state refrigeration applications. It is worth noting that a detailed description of the crystal structure, the microstructure and tuning properties of the BSTS-x samples have been reported elsewhere [26]. Besides solid-state cooling applications, BT-based materials have also demonstrated potential applications for energy storage capacitors [27–31].
Structural, dielectric, ferroelectric and electrical properties of lead-free Ba<inf>0.9</inf>Sr<inf>0.1</inf>Ti<inf>0.9</inf>Sn<inf>0.1</inf>O<inf>3</inf>ceramic prepared by sol-gel method
2021, Materials Today: ProceedingsCitation Excerpt :These findings indicate that BSTSn ceramics are very promising for energy storage applications. It is worth to mentioning that the maximum applied field of BSTSn in our study is very high than the one applied for BSTSn ceramics prepared by the solid-state method [23]. This result demonstrates that the sol–gel method is suitable for synthesizing ceramics with moderate breakdown strength.