Ferroelectric Properties Of BaTiO3 Research Articles

Effect of Sr substitution on the structural, dielectric and ferroelectric property of BaTiO3

We have performed a comprehensive study to explore the effect of Sr substitution on the structural and ferroelectric properties of BaTiO3(BTO) with compositions Ba1-xSrxTiO3for 0 ⩽x⩽ 1. The room temperature structural investigation inferred that the samples with compositionsx> 0.30 has cubic phase instead of tetragonal as for pristine BTO. The temperature dependent dielectric studies illustrate that all well-known three structural phase transitions of BTO are coming closer to each other and the cubic phase is shifted towards lower temperature with increasing Sr content. The frequency dependent dielectric measurements show that there exists the mesoscopic subdomain, whose relaxation time decreases with increasing Sr concentration. The Sr substitution enhanced the ferroelectric properties and maximum remnant polarization at room temperature is observed for 20% Sr substituted sample. The frequency dependent dielectric measurements illustrate the relaxation which could be due to the mesoscopic subdomain, and its relaxation time decreases with increasing Sr concentration. The frequency dependentP-Emeasurements at room temperature infer that for 30% Sr substituted sample, the ferroelectric domain switching is dominated by the rate of nucleation whereas in other compositions forx< 0.3, it is governed by the domain wall speed. The Raman measurements infer the rearrangement of the domain configuration with Sr substitution. Modification in the intensity of the E(TO4) and A(TO3) Raman modes with electric field is also observed for 30% Sr substituted sample and the origin of this is also discussed.

Investigating the effect of Mo doping on structural and ferroelectric properties of BaTiO3 using electron microscopy

The effect of Molybdenum (Mo) doping in pure barium titanate at Ti site has been investigated using electron microscopy, x-ray diffraction and dielectric and impedance spectroscopy. The room temperature XRD data confirms the formation of Mo substituted BaTi0.94Mo0.06O3 in tetragonal symmetry. Even with the minimal doping of Mo, the first two structural transition shifts to the lower temperature by 60 and 30 K, respectively, as compared to pure barium titanate, confirmed via dielectric, polarization and x-ray diffraction measurements. In Mo doped BaTiO3, the cubic to tetragonal phase transition has been observed at ∼335 K, tetragonal to orthorhombic at ∼250 K. The orthorhombic to rhombohedral transition remains almost unaffected with Mo doping. Furthermore, transmission electron microscopy (TEM) has been employed to see the changes in microstructure/domain structure across various ferroelectric phases below 335 K which confirms the emergence of multiple twins in different ferroelectric phases.

Ferroelectric BaTiO3 Regulating the Local Electric Field for Interfacial Stability in Solid-State Lithium Metal Batteries.

Solid-state Li metal batteries (SSLMBs) are widely investigated since they possess promising energy density and high safety. However, the poor interfacial compatibility between the electrolyte and electrodes limits their promising development. Herein, a robust composite electrolyte (poly(vinyl ethylene carbonate) electrolyte with 3 wt % of BaTiO3, PVEC-3BTO) with excellent interfacial performance is rationally designed by incorporating ferroelectric BaTiO3 (BTO) nanoparticles into the poly(vinyl ethylene carbonate) (PVEC) electrolyte matrix. Benefiting from the high dielectric constant and ferroelectric properties of BTO, the interfacial compatibility between electrolytes and electrodes was significantly improved. The enhanced Li+ transference number (0.64) of solid electrolyte and in situ generated BaF2 inorganic interphase contribute to the enhanced cycling stability of PVEC-3BTO based Li//Li symmetrical batteries. Furthermore, the antioxidation ability of PVEC-3BTO has also been enhanced by modulating the local electric field for good pairing with high-voltage LiCoO2 material. Therefore, in this work, the mechanism of BTO for improving interfacial compatibility is revealed, and also useful methods for addressing the interface issues of SSLMBs have been provided.

Experimental and first-principles investigation of structural, electronic, optical, elastic and ferroelectric properties of BaTiO[formula omitted

Structural, electronic, optical, elastic and ferroelectric properties of lead-free BaTiO3 perovskite has been investigated experimentally and theoretically by DFT + U calculations with U = 5 eV using Quantum ESPRESSO code. The ceramic sample was synthesized through solid-state reaction method and its detailed structural investigation done by combined Rietveld (JANA 2020), Pair Distribution Function (PDF) and Raman analysis. The calculated structural properties including the frequency position of Raman lines are found to be in good agreement with experimental results and the electronic study shows that the calculated band structure of tetragonal BaTiO3 at Γ point has an direct energy gap (Eg) about 3.43 eV. Optical parameters and also the elastic constants were computed and compared with the available experimental data. Spontaneous polarization of 0.34 C/m2 for tetragonal BaTiO3 was calculated using Berry phase calculation and it is comparable with the experimental value of 0.20 C/m2.

Enhancement in the magneto-dielectric and ferroelectric properties of BaTiO3 – CoFe1.9Yb0.1O4 core-shell multiferroic nanocomposite

Herein we report the dielectric, ferroelectric, magnetocapacitance and energy storage density properties of CoYb0.1Fe1.9O4-BaTiO3 core-shell multiferroic nano-composite synthesized by the combination of co-precipitation and sol-gel method. The XRD spectra revealed that the ferroelectric BT phase is compatible with the magnetic YbCFO phase. Scanning Electron microscopy (SEM), Energy-Dispersive X-ray spectroscopy (EDS) and Transmission Electron Microscopy (TEM) confirmed the formation of core-shell like structure in the composite. The magnetic and ferroelectric phase preserves their basic individual properties in the core–shell form. The temperature dependence of dielectric permittivity showed a sharp phase transition from cubic to tetragonal structure of the core-shell composite at 312.726 K. Frequency dependent dielectric study shows an enhanced value of permittivity (36905.0218) along with low dielectric losses (1.354). It was found that the prepared composite exhibited moderate values of saturation magnetization (3.379 emu/g) and polarization (5.146 μC/cm2) along with low remnant polarization (1.777 μC/cm2) at room temperature. Moreover, we also observed enhanced energy storage efficiency (60%) and magneto-capacitance (5.853%) which are explained due to strong interfacial coupling and reduced leakage current, making this composite promising for multifunctional device applications.

Structural correlations in the enhancement of ferroelectric property of Sr doped BaTiO3

The effect of Sr doping in BaTiO3 (BTO) with nominal compositions Ba0.80Sr0.20TiO3 (BSTO) have been explored on its structural, lattice vibration, dielectric, ferroelectric and electrocaloric properties. The temperature dependent dielectric results elucidate the enhancement in dielectric constant and exhibit three frequency independent transitions around 335, 250 and 185 K, which are related to different structural transitions. All these transitions occur at lower temperature as compared with pristine BTO, however; remnant electric polarization (Pr) of BSTO is much higher than in BTO. The value of Pr is ∼5 μC cm−2 at room temperature and the maximum Pr ∼ 8 μC cm−2 is observed at tetragonal to orthorhombic and orthorhombic to rhombohedral transitions. The electro-caloric effect shows the maximum adiabatic change in temperature ΔT ∼ 0.24 K at cubic to tetragonal transition. The temperature dependent synchrotron x-ray diffraction and Raman results show correlations between Pr, crystal structure and lattice vibrations. Our results demonstrate the enhancement in ferroelectric properties of BTO with Sr doping. The origin of the enhancement in ferroelectric property is also discussed in correlations with the appearance of superlattice peak around room temperature due to TiO6 octahedral distortion. These enhanced properties would be useful to design lead free high quality ferroelectric and piezoelectric materials.

Ferroelectric relaxor properties characterized by dynamic mechanical analysis

In this article, a dynamic mechanical analyzer (DMA) was applied to investigate the mechanical properties of ferroelectric BaTiO3 and PZT ceramics. Ferroelectric to paraelectric phase transitions were clearly revealed and obvious low frequency relaxation behaviors were characterized. The activation energy of relaxation peak and relaxation limit time of BT was theoretically analyzed using the Arrhenius relationship. The relaxation mechanism of fine grain size (<1 μm) BaTiO3 and hard PZT-8 and PZT-4 ceramics was explained, while no relaxation behavior was found in larger grain size BaTiO3 and soft PZT-5H ceramics.

Developmental Prospects of the Methods for Synthesizing Titanates of the Perovskite-Type Structure and Their Doping with Rare-Earth Elements

A review of methods for fabricating titanates of a perovskite-type structure and their doping with rare-earth elements is presented. The results of the scientific research of authors from different countries related to the study of the effect of doping titanates of the perovskite structure by rare-earth elements on their electromagnetic properties are discussed. The content of the work also includes information on the use of titanates of the perovskite-type structure in various industries. A comparative analysis of some morphological properties (particle size and structure) and electromagnetic characteristics (dielectric constant, Curie temperature, and modulus of longitudinal oscillations (d33)) of powders fabricated (and doped) by different methods is carried out by the example of barium titanate (BaTiO3). Procedures for fabricating BaTiO3 by various methods, such as solvothermal, hydrothermal, sol–gel, chemical deposition, and solid-phase sintering, are described. The results of studying the influence of the variation in process parameters (temperature, pH, composition of the initial mixture of materials, and concentration of reagents) on the phase, morphology, and formation rate of BaTiO3 particles during the hydrothermal synthesis (with the use of BaCl2, TiCl4, and NaOH as initial materials) are presented. The experiments on studying the influence of the microwave-radiation power during the solid-phase sintering of BaCO3 and TiO2 on dielectric and ferroelectric properties of BaTiO3 are also presented. An analysis of fabrication methods of BaTiO3 and its doping by rare-earth elements results in the statement that the hydrothermal method and solid-phase sintering, including the application of the microwave radiation, are currently the most promising fabrication technologies of materials with the perovskite-type structure with specified properties.

Flexible, ferroelectric nanoparticle doped polymer dispersed liquid crystal devices for lower switching voltage and nanoenergy generation

Flexible polymer dispersed liquid crystal (F-PDLC) devices were fabricated using transparent conducting ITO/PET film. Polymerization induced phase separation (PIPS) method was used for pure and ferroelectric BaTiO3 (BTO) and ZnO doped PDLC devices. The distribution of nanoparticles in the PDLC and the formation of micro cavities were studied using field emission scanning electron microscopy (FESEM). It was observed that the addition of ferroelectric BTO nanoparticles has reduced the threshold voltage (Vth) and saturation voltage (Vsat) of FNP-PDLC by 85% and 41% respectively due to the spontaneous polarization of ferroelectric nanoparticles. The ferroelectric properties of BTO and ZnO in the fabricated devices were investigated using dynamic contact electrostatic force microscopy (DC EFM). Flexing the device can generate a potential due to the piezo-tribo electric effect of the ferroelectric nanomaterial doped in the PDLC matrix, which could be utilized as an energy generating system. The switching voltage after multiple flexing was also studied and found to be in par with non-flexing situations.

The effects of PbZn1/3Nb2/3O3-doping on structural, thermal, optical, dielectric, and ferroelectric properties of BaTiO3 ceramics

Low-lead (1-x)BT-xPZN (x = 0, 0.025, 0.05, 0.075, 0.10, 0.125, and 0.15) ceramics were successfully synthesized by the spark-plasma-sintering method for the first time. Their phase transition behavior as well as structural, thermal, optical, and electrical properties was investigated. These materials exhibit the structure of perovskite-type solid solutions and undergo a sequence of phase transitions, typical of pure BaTiO3 (BT). The dielectric test results revealed that with the increase in the PbZn1/3Nb2/3O3 (PZN) content, the frequency dispersion of electric permittivity increases, whilst the dielectric/ferroelectric properties tend to deteriorate, which is characteristic of relaxor-type behavior. Therefore, it is reasonable to suppose that these ceramics progressively lack long-range ordering. These effects are due to the competition between lone-pair electrons' induced changes in the A-O band upon Pb2+ addition and ionic size differences. In general, the transition temperatures observed by dielectric analyses are in good agreement with those obtained from X-ray diffraction and differential scanning calorimetry measurements. The BT-PZN system may help to understand why relaxor behavior appears in perovskite-based materials. It appears that these materials can become a good starting point for the development of new low-lead electronic ceramics.

Effect of magnetic ion (Mn) doping on structural, ferroelectric and magnetic properties of Ba0.90Mn0.10TiO3

Synthesis, formation, structural phase transition, dielectric and magnetic properties of polycrystalline Ba0.90Mn0.10TiO3 (BMTO) ceramic have been investigated to study the effect of magnetic ion (Mn) doping at Ba-site in the well-known ferroelectric (FE) material BaTiO3 (BTO). The polycrystalline ceramic BMTO has been prepared via solid state reaction route. The Wyckoff-site occupancy of the substituted Mn has been determined through x-ray diffraction (XRD) and soft X-ray absorption measurement via confirmation of its oxidation state to be 2+ and that of Ti to be 4+. The temperature dependent XRD, dielectric and pyroelectric studies show all the known transitions similar to the pristine BTO. However, the transition temperatures (Tc) were found shifted towards lower temperatures as compare to the pristine BTO. The shifts in Tc corresponding to cubic-tetragonal and tetragonal-orthorhombic transitions are significant as compared to that of orthorhombic-rhombohedral transition. Frequency dependent dielectric measurements show the space-charge related dielectric relaxation. The dc-magnetization measurements show antiferromagnetic interactions in BMTO. Our results also address the role of Ba site on the ferroelectric properties of BTO.

Ferroelectric BaTiO3 nanoparticles: Electron structure and properties

Properties of BaTiO3 nanoparticles, transition into the ferroand paraelectric BaTiO3 phase, and dependence of Curie temperature Tc(BaTiO3) on the energy of excited states of a Ba atom are studied in the terms of the nanoparticle shell theory. Dimensional properties of ferroelectric BaTiO3 and PbTiO3 nanoparticles are compared.

Diluted magnetic ferroelectric effect in BaTi0.9Hf0.05Co0.05O3 ceramic

We report that magnetism, especially ferromagnetism, can be induced in a nonmagnetic ferroelectric oxide such as barium titanate (BaTiO3) with choosing of suitable dopants. High-density polycrystalline sample of BaTi0.9Hf0.05Co0.05O3 was prepared using solid-state sintering route, and the effect of Co and Hf substitution on structural, magnetic and ferroelectric properties of BaTiO3 was studied. The magnetic order obtained in the above sample is of intrinsic in nature. Ferromagnetic behavior shown in the BaTi0.9Hf0.05Co0.05O3 ceramic may be attributed to the effective exchange interactions between oxygen vacancies and Co ions. BaTi0.9Hf0.05Co0.05O3 ceramic has also shown ferroelectric (lossy type) behavior.

Structural, ferroelectric, electronic and transport properties of BaTiO3/Pt heterostructures grown on MgO(0 0 1)

Heteroepitaxial BTO(001)/Pt(001) films are grown on MgO(001) by PLD.As grown BTO films are in a single-domain state and polarized downward.The band gap of ultrathin heteroepitaxial BTO layer strongly depends on thickness.Cr/BTO(3nm)/Pt based FTJ: tunneling electroresistance Rup/Rdown up to 30. In this work, we describe the structural and ferroelectric properties of BaTiO3(001)/Pt(001) heterostructures grown by pulsed laser deposition on MgO(001) substrates. By combining HAXPES results on the electronic band line-up at the interfaces of Cr/BaTiO3(001)/Pt(001) trilayers with REELS data of the band gap in ultrathin BaTiO3 layers we reconstruct the shape of the potential energy barrier profile across the corresponding ferroelectric tunnel junction (FTJ). I-V characteristics of FTJs with sub-µm Au/Cr top electrodes reveal a tunneling electroresistance change by the factor of ~30 following the ferroelectric polarization reversal. I-V curves are fitted with the experimentally determined electrostatic potential energy profile for the particular polarization direction to derive the quantitative changes in the barrier profile upon polarization reversal.

Influences of Zn and Mn ions co-dopants on the optical and ferroelectric properties of BaTiO&lt;SUB&gt;3&lt;/SUB&gt; thin films

Influences of Zn and Mn ions co-dopants on the optical and ferroelectric properties of BaTiO&lt;SUB&gt;3&lt;/SUB&gt; thin films

Ferroelectric, electrical, and structural properties of Dy and Sc co-doped BaTiO3

Ba1−xDyxTi1−xScxO3 ceramics, 0 ≤ x ≤ 0.075, were prepared and the influence of Dy and Sc co-doping on the ferroelectric, electrical and structural properties of BaTiO3 (BT) investigated. A solid solution limit of x ≈ 0.05 was established using X-ray diffraction, and all compositions x ≤ 0.05 were tetragonal at room temperature. Fixed-frequency capacitance measurements showed the temperature of the cubic to tetragonal phase transition, TC, decreased non-linearly with increasing x and the associated permittivity peak broadened, with frequency-dependent ‘relaxor’-type behaviour observed for cubic x = 0.075. In addition, the magnitude of the relative permittivity at TC showed a negative dependence on x, decreasing from ∼11700 for x = 0 to ∼6950 for x = 0.05. In contrast to the non-linear decrease in TC, the tetragonal to orthorhombic and orthorhombic to rhombohedral phase transition temperatures decreased linearly at rates of ∼40 and ∼28 °C mol%−1 of DyScO3, respectively. The effect on the ferroelectric properties of BT was to quadruple the coercive field, from ∼0.9 kV cm−1 for x = 0 to ∼4.4 kV cm−1 for x = 0.025, without affecting the remnant polarisation, ∼10 to 11 µC cm−2 for x = 0 to 0.025. Finally, the non-linear decrease in TC is discussed in terms of the contributions of the mean size and statistical variance of the cations on the A and B sites of the perovskite, ABO3, lattice and the replacement of Ti4+ with Sc3+ cations.

First-principles study for surface tension and depolarizing effect on ferroelectric properties of BaTiO 3 nanowires

The spontaneous polarization in ferroelectric (FE) nanowires (NWs) can be considerably enhanced due to the nanosize confinement by the first-principles calculations. The spontaneous polarization in a fully-relaxed BaTiO 3 NW with 2.0 nm in diameter is 1.18 times higher than that of bulk counterpart. The ferroelectric properties of the wire are found to generally depend on its dimensions through effects of the surface tension and near-surface depolarizing effect. The surface tension seems to be crucial for the giant enhancement of spontaneous polarization.

Strain effect on ferroelectric behaviors ofBaTiO3 nanowires: a molecular dynamics study

In this paper, a molecular dynamics method is utilized to investigate the strain effect onthe polarization distribution, piezoelectric coefficient, and hysteresis behaviors ofBaTiO3 nanowires. The axial polarization changes almost linearly with the strainover a relatively large range, and the ferroelectricity vanishes under a criticalcompressive strain. With the nanowire becoming thicker, the piezoelectric coefficientincreases, and approaches its counterpart for bulk material when the diameter islarger than 2.4 nm. It is also revealed that a pre-tension strain can induce theemergence of a stepwise hysteresis loop while a pre-compression strain can lead tothe disappearance of the stepwise shape. Furthermore, the strain effect and sizeeffect are found to play some equivalent roles in the ferroelectric properties ofBaTiO3 nanowires.

Dynamical behavior of the phase transition of strained from atomistic simulations

Abstract Using an atomistic shell model we study the temperature dependence of the ferroelectric properties of BaTiO 3 under biaxial compressive strain applicable to growth on perovskites substrate. Molecular dynamics simulations show a “ r → c → p ” sequence of phase transitions when temperature is increased, and the absence of an “ ac phase”. The first-order paraelectric-to-ferroelectric phase transition presents in bulk changes to a second-order one as a consequence of the in-plane constraint imposed by the mechanical boundary conditions. From the tetragonal ferroelectric c phase, the transition takes place in a finite range of temperature where the lattice parameter normal to the plane keeps approximately constant until T c is reached. Analysis of the local polarization behavior reveals an order–disorder dynamics as the dominant mechanism of the transition.

X-Ray Absorption Spectroscopy Study of Ba1-xSrxTiO3 (x = 0.0-0.2) at the Ti-K and Ba-LIII Edges

Barium titanate, BaTiO3 is a significant material for electronic components. It was known that Sr2+ substitution on Ba ion can strongly modify ferroelectric properties of BaTiO3 but the structural change has not been fully understood. An X-ray absorption spectroscopy at the Ti K-edge (4966 eV) and the Ba LIII-edge (5247 eV) was employed to investigate the structure of Ba1-xSrxTiO3 (BSTO) with 0&lt;x&lt;0.20. Results suggested that Ba2+ did not change its position with Sr2+ substitution. On the other hand, Ti4+ atoms gradually displaced as Sr2+ is increased.