Enhancement Of Dielectric Constant Research Articles

The Effects of Postdeposition Anneal and Postmetallization Anneal on Electrical Properties of TiN/ZrO2/TiN Capacitors

Metal–insulator–metal (MIM) capacitors based on zirconia (ZrO2) are widely used in dynamic random access memories (DRAMs). As the smaller and smaller feature size in DRAM chips requires higher and higher capacitance density, it is necessary to minimize the equivalent oxide thickness (EOT) of ZrO2, or maximize its dielectric constant ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${k}$ </tex-math></inline-formula> ) while maintaining low leakage currents. Annealing is an effective method to achieve high <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${k}$ </tex-math></inline-formula> -values. In this article, we report the impact of two mainstream annealing methods on the electrical properties of ZrO2-based MIM capacitors. The results showed that the dielectric constant of ZrO2 reached 41.5 after postdeposition anneal (PDA) at 350 °C, while grazing incidence X-ray diffraction (GIXRD) measurements indicated the formation of high- <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${k}$ </tex-math></inline-formula> tetragonal phase. In contrast, similar dielectric constant enhancement requires much higher temperature (450 °C) for postmetallization anneal (PMA). When similar high- <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${k}$ </tex-math></inline-formula> value was reached, the leakage current density of PDA samples was three orders of magnitude lower than that of PMA ones at 0.8 V. Additionally, lower annealing temperature also decreases the parasitic EOT at the interface, which was formed by the interaction of ZrO2 and TiN electrodes. Overall, we found PDA is more beneficial for achieving a higher dielectric constant (>40), lower leakage currents, and lower EOT at lower temperatures compared with PMA, and potentially more suitable for industrial DRAM fabrication process.

Enhancement of microstructure characteristic and dielectric constant of BaMn0.05Ti0.95O3 ceramics

Barium Titanate or BaTiO3, a ferroelectric material with good dielectric properties, is widely studied. The performance of BT is influenced by synthesis and doping. Here, Barium Titanate has been doped with Manganese via the co-precipitation procedure sintered at 900°C and 1000°C. The purposes of this study were to examine the microstructure and dielectric constant of BaMn0.05Ti0.95O3 with variation sintering temperatures at 900°C and 1000°C. The testing employed X-Ray Diffraction (XRD), Fourier Transform Infrared (FTIR), and Resistance Capacitance Inductance (LCR Meter). The XRD data exposed that the crystal size of the BaMn0.05Ti0.9503 sample enlarged from 48.27 nm to 72.41 nm with increasing sintering temperature. The analysis results using FTIR exhibited the existence of Ba-O and Ti-O bonds which confirmed the perovskite structure of BaTiO3. FTIR data also indicated the presence of C-H atomic bonds, which is the peak of impurities in the carbonate phase. The C-H bond vibration decreased at the higher sintering temperature. The dielectric constant value was obtained from the measurements using an LCR meter. In conclusion, increasing the sintering temperature improved the dielectric constant of BaMn0.05Ti0.95O3 from 119 to 386.

Extremely Reduced Dielectric Constant and Band Gap Enhancement in Few-Layered Tungsten Disulfide Nanosheets.

Highly crystalline few-layered tungsten disulfide (WS2) nanosheets were synthesized via a cost-effective, low-temperature hydrothermal route. X-ray diffraction and HR-TEM analysis confirmed the formation of hexagonal nanosheets with thickness of ∼6-8 nm. Raman analysis and AFM results confirmed the few-layered 2H phase of WS2 nanosheets. The UV-vis study shows absorption peaks at 219 and 271 nm with large band gap value of ∼3.12 eV for WS2 nanosheets. Surprisingly, WS2 nanosheets show a dielectric constant of approximately ε' ≈ 5245, whereas bulk WS2 material exhibits a dielectric constant of 7482373. An almost 1426-fold decrease in the value of dielectric constant for the WS2 nanosheet is observed. Such an extreme reduction in dielectric constant and observance of large band gap in WS2 nanosheet were observed for the first time. The present study reveals the excellent and unusual optical and dielectric properties for their potential application in optoelectronic, dielectric, solar, phosphor, and various nanoelectronic devices.

Insights in the enhancement of electrical conductivity and dielectric constant of epoxy-carbon nanotubes decorated with CaCO3-derived from waste eggshell hybrid composites

New insights in the development of epoxy hybrid composites using CNTs decorated with CaCO3 derived from waste eggshell (CaCO3-ESp) have been studied. The composite was produced by the solution stirring method. The dielectric constant, electrical conductivity, and morphology of the samples were determined. The dielectric constant and electrical conductivity were enhanced after the modification of the CNTs with CaCO3-ESp. The high electrical conductivity and dielectric constant obtained were attributed to the high electron mobility of CaCO3-ESp-CNTs, which helps to enhance the conductivity of the epoxy. It was found that used eggshells can be used to make sure that CNTs are spread out well when making conductive polymers for isotropic conductive adhesives, assemblies, and packaging for electronics.

The Effects of A-site Doping on Crystal Structure, Microstructure and Electrical Properties of (Ba0.85Ca0.15) Zr0.1Ti0.9O3 Ceramics

(Ba0.85Ca0.15) Zr0.1Ti0.9O3 (BCZT) ceramics with donor (La3+ and Bi3+ ions) and acceptor (Na+ ions) doping at the A-site were fabricated in this study. The effects of crystal structure, microstructure, and chemical defects on all samples’ dielectric properties and piezoelectric coeffi cient (d33) were observed. Bi3+ ions decreased grain size, decreased phase transition temperature, and caused the diffuse dielectric spectrum, resulting in a low d33 value. Na+ ions induced abnormal grain growth, leading to enhancement in maximum dielectric constant; meanwhile, the phase transition temperature increased. The d33 value of Na-doped BCZT was comparable with BCZT ceramic. The addition of La3+ ions increased the phase transition temperature and decreased grain size. The d33 value of La-doped BCZT was lower than BCZT ceramic. The result suggested that BCZT, BCZT-Na, and BCZT-La ceramics could be alternative materials for piezoelectric energy harvesting devices.

Effect of TiO2 as Filler in NaCl: Possible Applications in Ionic Storage Systems

High dielectric capacitors are increasingly used for energy storage in sustainable nanotechnologies. Here, we observed large enhancement of dielectric constant by 3 order at frequency 1kHz with moderate loss when TiO2 is added as a filler in NaCl bulk matrix. The TiO2 nanoparticles are synthesized via sol gel process and is subsequently added in varying weight percentage x in the ionic matrix of NaCl, which is represented as TiO2(x)NaCl. The parameters like dielectric constant, dissipation Loss and ac conductivity are measured with varying fraction of TiO2 in frequency range less than 25 KHz. The steady increase of dielectric constant with increasing filler content at low frequency indicates percolation type behavior which accounts for the first dielectric peak at x= 50. The dielectric loss is found to be around 1 for x< 45 whereas it tends to increases with higher filler fraction. Moreover, the frequency dependent polarization in this composite system also accounts for hopping type behavior of mobile charge carriers contributed by TiO2 as confirmed from ac conductivity measurement. Further, the samples are characterized by X-ray diffraction and Field emission scanning electron microscopy in order to study the structure and morphology of the samples. Overall, TiO2 incorporation strongly improves the dielectric behavior of the ionic matrix at low frequency, making it suitable for super dielectric material (SDM).

Nonlinear Quantum Electrodynamics in Dirac Materials.

Classical electromagnetism is linear. However, fields can polarize the vacuum Dirac sea, causing quantum nonlinear electromagnetic phenomena, e.g., scattering and splitting of photons, that occur only in very strong fields found in neutron stars or heavy ion colliders. We show that strong nonlinearity arises in Dirac materials at much lower fields ∼1 T, allowing us to explore the nonperturbative, extremely high field limit of quantum electrodynamics in solids. We explain recent experiments in a unified framework and predict a new class of nonlinear magnetoelectric effects, including a magnetic enhancement of dielectric constant of insulators and a strong electric modulation of magnetization. We propose experiments and discuss the applications in novel materials.

Heterogeneous BaTiO3@Ag core-shell fibers as fillers for polymer dielectric composites with simultaneously improved dielectric constant and breakdown strength

Interfacial polarization between fillers and polymer matrix in polymer composites would be responsible for enhancement of dielectric constant (εˊ), but the dielectric mismatch between fillers and polymer also leads to an undesirable electric breakdown. Herein, we successfully developed a core-shell structured barium titanate@silver (BaTiO3@Ag, BT@Ag) novel heterogeneous fiber via coaxial electrospinning followed by calcination technology, to simultaneously improve the dielectric property and breakdown strength (Eb) of poly(vinylidene fluoride) (PVDF)-based composites. Dielectric measurement reveals that PVDF/BT@Ag composites have an enhanced εˊ, low dielectric loss (tan δ) and moderately increased Eb. Since the core-shell structured fibers help in tailoring the local electric field around the interface, but also provide double interfacial polarization, which effectively improves the dielectric properties of the composites. When the loading of BT@Ag reached up to 10 wt%, the εˊ increased to 19.4 @1 kHz while the Eb had maximum value of 389.1 MV/m, finally resulting in an improvement of Ue. Moreover, the incorporation of BT@Ag obviously improves the mechanical properties of composites. It is expected that these results would further inspire the design of fillers with novel architecture for high-performance dielectric polymer composites.

Magnetic and dielectric properties of ZnFe2O4/nanoclay composites synthesized via sol-gel autocombustion

The current research aims to systematically investigate the influence of octadecylalkylammonium intercalated montmorillonite (ODA-MMT) as supporting material on the crystallographic, morphological, magnetic and dielectric characteristics of Zn ferrite (ZnFe2O4) nanoparticles. There have been executed the synthesis of ZnFe2O4 samples through sol-gel auto-combustion method for a variety of ODA-MMT contents (0–6 wt% in step of 2). XRD, FESEM, FTIR techniques have been employed for the structural verification of naked and ODA-MMT supported ZnFe2O4, while the magnetic and dielectric behaviors have been examined meticulously. The XRD data are augmented by Scherrer method, W–H and W-A analysis to consolidate different microstructural parameters such as crystallite size, strain, dislocation density, etc. XRD measurement reveals the desired phases (cubic spinel phases) of ZnFe2O4. The incorporation of ODA-MMT as a supporting material in ZnFe2O4 leads to a decrement of crystallite size. The values of saturation magnetization are found to be in the range of 51.6–58.1 emu/g in ODA-MMT supported compounds which is much higher than the value of 41.6 emu/g found for 0 wt% (‘naked’) Zn ferrite. Dielectric constant enhanced significantly (~165% in 4 wt% ODA-MMT supported compound) when ODA-MMT is used as a supporting material for Zn ferrite nanoparticles. Enhancement of dielectric constant in ODA-MMT supported Zn ferrite is appeared to be related with the degree of exfoliation of montmorillonite layers into ZnFe2O4 particles.

FT-IR, ultrasonic and dielectric characteristics of neodymium (III)/ erbium (III) lead-borate glasses: experimental studies

Lead-borate glasses reinforced by Er3+ and Nd3+ ions with the form 50B2O3–30CaO–20PbO-0.5Er2O3-x (Nd2O3), where x = 0–1.50 mol% labelled as S1–S7 were fabricated utilizing the traditional melt quenching technique. Physical, structure, ultrasonic mechanical, and dielectric properties of the proposed glasses were investigated. The density of the glass system showed a decrement from 3757 to 3646 kg/m3. The molar volume increased from 2.566 × 10−5 m3 for glass sample S1 to 2.831 × 10−5 m3 for glass sample S7. Introduction of Nd3+ and Er3+ ions induced amplified changes in the local field on the lead ions giving rise to occur the forming of [PbO4] units. The average boron–boron separation (dB–B) varied from 3.49 × 10−10 to 3.61 × 10−10 Å for samples S1 and S7, respectively. The Nd3+ ions concentration takes values from 0 for S1 glass sample to 10.7 × 1025 ions m−3 for S7 glass sample. The N4 decreased with increasing rare earth ions content in glass composition. In contrast, the N3 which refers to the absorption band area related to the [BO3] group, increased. VL and VS increased from 5289 to 5529 ms−1 and from 2906 to 3093 ms−1, respectively with addition of Er3+ and increasing of Nd3+ ions from 0 (S1 sample) to 1.5 (S7 sample) mol%. The enhancement in dielectric constant was clearly observed. It increased from 25.4 to 55.3 with the change in composition from S1 to S7 at 50 kHz frequency. The ac conductivity was enhanced with increasing applied frequency especially at the high-frequency range.

Studies on the multiferroic properties and impedance analysis of (La, Cu) BiFeO3 prepared by sol-gel method

Perovskite BiFeO3 (BFO), and Bi1-xLaxFe0.98Cu0.02O3 (x ≤ 0.05) multiferroic ceramics were prepared by conventional sol-gel method. The influence of (La, Cu) co-doping on the structure, morphology, magnetic, ferroelectric and dielectric behavior were studied comprehensively. X-ray diffraction confirmed that the BFO samples possess rhombhedral structure. The crystallite size, lattice constant, etc were affected by La doping. Ferromagnetic properties were distrubed due to external doping. Enhanced ferroelectic properties like increased remanant polarization and reduced leakage current were achieved by La-substitution. Significant enhancement of dielectric constant may be attributed to Maxwell-Wagner effect. Impedance spectroscopy analysis suggests the effect of grain and grain boundary on the electrical properties of the BFO ceramics. Cole-Cole plots specifies non-Debye type of behavior. Enhanced dielectric constant, reduced loss and decreased leakage current of (La, Cu) doped BFO suggest these ferrites to be promising room temperature perovskite multiferroic materials for lead-free photovoltaic devices.

Systematic characterization of THz dielectric properties of multi-component glasses using the unified oscillator model

A terahertz (THz) dielectric property characterization method based on a unified single oscillator model has been developed and applied to a variety of multi-component silicate oxide glasses. The experimental values of dielectric constant determined by THz time-domain spectroscopy (TDS) in the sub-THz region have been confirmed to agree well with the values calculated by the single oscillator model which incorporates the local field effects and the material’s ionicity. This has provided a unified formulation that enables systematic determination of the key physical parameters solely from the high-frequency (optical) and low-frequency (sub-THz) dielectric constants and characteristic resonance frequency in the (sub-)THz region. The low-frequency dielectric constant has been demonstrated to be fully determined by a single parameter of the microscopic total susceptibility. Also, the polarization ionicity, which is defined by the ionic fraction in the microscopic total susceptibility, has been found to be a good indicator to represent the ionic nature of the material. Through this analysis, an increasing trend of the effective ionic charge has been found in high-dielectric constant glasses such as oxyfluorosilicate glasses, and the physical mechanism of their dielectric constant enhancement has been discussed. The present method is expected to be applied to design and characterize dielectric properties of a wide range of multi-component glasses and other isotropic, insulating materials.

Structural, dielectric, and conductivity studies of strontium-doped Gd2NiMnO6 perovskite

In this contribution, the structural, electrical, dielectric, and microstructural properties of double perovskite Gd2NiMnO6 doped with strontium were presented. The strontium-doped double perovskite Gd2–xSrxNiMnO6 (x = 0, 0.1 & 0.3) was synthesized by using the solid-state reaction method. The X-ray diffraction and scanning electron microscopy characterization techniques were used to investigate the structural and surface morphological properties. The Rietveld refinement depicted the formation of pure phase having a P21/n monoclinic space group. A decrease in grain size and crystallite size was found with the dopant concentration increase, resulted in enhancement of dielectric constant of the material. The frequency- and temperature-dependent dielectric study revealed increase in dielectric constant and decrease in dielectric loss with the increase in dopant concentration. Apart from dielectric studies, the conductivity studies revealed decrease in conductivity with the increase in Sr doping, supporting the dielectric properties. In conclusion, the synthesized material is functional, has high dielectric constant, low dielectric losses and low conductivity, and, hence, it can be considered as a potential candidate for high k dielectric materials.

Effect of Gd on structural, dielectric and electrical transport properties of multiferroic ceramic composite BiFeO3–NaNbO3

The multiferroics composite of (1- x)(BiFe1-yGdyO3)– xNaNbO3 (BFGNNO) with x = 0.25, 0.45 and y = 0.10, 0.20 were prepared by a high-temperature solid-state reaction technique. Structural characterization was performed by X-ray diffraction which confirms the formation of the ceramic and the materials show rhombohedral structure at room temperature. Frequency and temperature dependence of dielectric constant (εr) and dielectric loss (tanδ) of samples were measured in wide range of frequency (100 Hz to 1 MHz) and temperature (25 °C to 450 °C) using an LCR meter. The analysis of the study shows that the εr and tanδ decreases with increasing frequency in the given range for all the samples which can be explained through the occurrence of dipole relaxation process. There is enhancement of dielectric constant observed with increasing the Gadolinium (Gd) concentration. The dielectric anomalies are observed in the studied sample at about 390 °C which found to be shifting towards higher temperature side on increasing the frequency. The frequency variation of ac conductivity shows that the compound obeys Jonscher's universal power law. The variation of ac conductivity with inverse temperature found to obey the Arrhenius equation and the materials show negative temperature coefficient of resistance (NTCR) behavior.

Surfactant free green synthesis of GOSiMa hybrid nanocomposite for charge storage application

Present work reveals the synthesis of graphene oxide-silica@magnesium oxide (GO-SiO2@MgO)/(GOSiMa) hybrid nanocomposite by using a green sol-gel technique from its constituent precursors GO sheets, tetraethyl orthosilicate (TEOS) and magnesium chloride (MgCl2). Broad ranges of characterization techniques like TEM, FESEM, EDAX, FTIR, XRD, DLS and BET are followed to investigate the hybrid composite. The cyclic voltammetry (CV) behaviour is studied at N2 and O2 atmosphere with Ag/AgCl electrode as a reference. The surface area of nanocomposites is found to be 107.59 m2/g with an average porosity value of 97.8602 Å. From the dielectric study, it is found that, synthesized GOSiMa nanocomposite has dielectric constant ε′ from 102 up to 2.5 × 104 with the minimal dielectric loss ε′′ of ≤102 at all range of temperature 22 °C–185 °C and frequency range of 103–106 Hz. The effect of polarization and atomic rearrangements are the prime factors for enhancement of dielectric constant. Conductivities (σac) of this hybrid nanocomposite are measured as 8 × 10−3 S/m in the low-frequency region at 1 kHz and 1 × 10−2 S/m at a high-frequency region of 2 MHz at a temperature of 160 °C for justifying the as-synthesized nanocomposite is a potential power electronics candidate for application in the charge storage device. The current work highlights the dielectric and charge storage potential of the prepared hybrid nanocomposite in a cost-effective and eco-friendly method.

Improved Electrical Properties Displayed by Mg2+-Substituted Cobalt Ferrite Nano Particles, Prepared Via Co-precipitation Route

In this reported study, magnesium-substituted cobalt ferrite nanoparticles (Co1−xMgxFe2O4, x = 0.0, 0.20, 0.35, 0.50) have been investigated. The samples were prepared via a wet chemical co-precipitation route and were calcinated at 800 °C for 6 h. The structural, electrical, and dielectric properties of these samples were studied using XRD, SEM, FTIR, impedance analyzer, and LCR meter. The XRD diffractograms established the development of FCC spinel arrangement with decreasing crystallite size from 20 to 30 nm without any additional impurity peak confirming the purity of the samples synthesized. The FTIR spectra established the existence of tetrahedral (A) and octahedral (B) lattice sites in the structural arrangement. The SEM images showed uniform nano-spherical particle formation with minimum porosity. No extra phase or impurity was found, confirming the effectiveness of the co-precipitation route. The dielectric properties of the synthesized samples measured at ambiance temperature against frequency range of 103 Hz to 5 MHz showed massive enhancement of dielectric constant (on the order of 104 at 100 Hz) which was comparable to traditional ceramics (having a dielectric constant in the range of 104–106), which are often rendered suitable for capacitor applications. Furthermore, the low values of dielectric loss tangent at high frequencies verified its potential usage in microwave applications. A significant contribution of both long- and short-range order in hopping as well as an increase in grain boundary density was confirmed by complex electric modulus analysis. The DC electrical resistivity measurement against increasing temperatures was done, showing a typical decreasing trend with increasing temperature, validating the semiconductor nature of synthesized nanoparticles with varying compositions. The drift mobility was further calculated from the DC resistivity data.

Sub-nanometer heating depth of atomic layer annealing

Conventional annealing techniques face tremendous challenges in nanoscale fabrication. For example, the heating depth of conventional annealing techniques is much greater than the critical dimension of nanoscale devices, resulting in excessive thermal budget and so degradation of device performance. In this study, the atomic layer annealing (ALA) technique of a sub-nanometer heating depth is demonstrated. ALA is an in-situ plasma treatment applied in the process of atomic layer deposition (ALD), resulting in delivery of energy to the surface of as-deposited thin films from the plasma. The ALA treatment introduced into each ALD cycle leads to significant enhancement of crystallinity, film density, and dielectric constant, as well as considerable suppression of leakage current and threading dislocation densities, of the AlN layer. These improvements of the AlN properties was degraded significantly with an increase of the cycle spacing of the ALA treatment in the ALD process, indicating the heating depth of the ALA technique is below 5 atomic layers. The result indicates that the ALA process of precise sub-nanometer heating depth plays a critical role to achieve high-quality nanoscale materials and devices.

Increased static dielectric constant in ZnMnO and ZnCoO thin films with bound magnetic polarons

A novel small signal equivalent circuit model is proposed in the inversion regime of metal/(ZnO, ZnMnO, and ZnCoO) semiconductor/Si3N4 insulator/p-Si semiconductor (MSIS) structures to describe the distinctive nonlinear frequency dependent capacitance (C-F) and conductance (G-F) behaviour in the frequency range from 50 Hz to 1 MHz. We modelled the fully depleted ZnO thin films to extract the static dielectric constant (εr) of ZnO, ZnMnO, and ZnCoO. The extracted enhancement of static dielectric constant in magnetic n-type conducting ZnCoO (εr ≥ 13.0) and ZnMnO (εr ≥ 25.8) in comparison to unmagnetic ZnO (εr = 8.3–9.3) is related to the electrical polarizability of donor-type bound magnetic polarons (BMP) in the several hundred GHz range (120 GHz for CdMnTe). The formation of donor-BMP is enabled in n-type conducting, magnetic ZnO by the s-d exchange interaction between the electron spin of positively charged oxygen vacancies {V}_{o}^{+} in the BMP center and the electron spins of substitutional Mn2+ and Co2+ ions in ZnMnO and ZnCoO, respectively. The BMP radius scales with the Bohr radius which is proportional to the static dielectric constant. Here we show how BMP overlap can be realized in magnetic n-ZnO by increasing its static dielectric constant and guide researchers in the field of transparent spintronics towards ferromagnetism in magnetic, n-ZnO.

Temperature dependent dielectric properties and ac conductivity of GdFe1−xMnxO3 (0 ≤ x ≤ 0.3) perovskites

We have synthesized the nano-crystalline samples of GdFe1−xMnxO3(0 ≤ x ≤ 0.3) via solid state reaction route and studied their dielectric properties and ac conductivity in detail. X-ray diffraction patterns show monophase structure of the samples in orthorhombic crystal symmetry (space group Pbnm). The enhancement in dielectric constant is registered on Mn doping at room temperature as well as with the rise in temperature at a constant frequency. The fitting of Cole–Cole plots indicate the non-Debye kind relaxation mechanisms in the samples. The real (Z′) and imaginary (Z″) components of impedance reduce with the increase in frequency and Mn ions in GdFeO3 lattice. Nyquist plots are fitted to a single semicircle that hints towards the single relaxation process. The ac conductivity (σac) is also increased with the frequency and follow the power law,σac(ω) = Aωs wherein the exponent ‘s’ reduces with frequency. We have estimated the activation energies with the help of ln(σ) versus 1/T plots that remain almost constant below 350 K and show variation with the Mn doping in GdFeO3 perovskite at temperatures 620–673 K. The polaron hopping energy (WM) in the framework of the correlated barrier hopping (CBH) and non-overlapping small polaron tunneling (NSPT) models have been calculated and its variation with temperature signifies thermally activated conduction mechanism in the studied materials.

Synthesis, characterisation and dielectric properties of low-loss Zr-doped barium strontium titanate materials

ABSTRACTA series of materials of the composition Ba0.7Sr0.3ZrxTi(1 − x)O3 (BSZT), where x = 0.00, 0.01, 0.02 and 0.03, were synthesised through the sol–gel method whereupon the manifestations of partial substitution of Ti4+ by Zr4+ on the structural and dielectric behaviour of Ba0.7Sr0.3TiO3 (BST) were studied. X-ray diffraction patterns of all samples showed the development of a single-phase crystalline perovskite structure. The dielectric behaviour of the ceramic samples has been studied in detail in the frequency range 10 Hz to 1 MHz at room temperature, and as a function of increase in temperature. The sample with 2% Zr recorded the highest dielectric constant. The dielectric loss values for all the BSZT compositions are remarkably low, tan δ = 0.021∼0.026 at 1 MHz, in contrast to the literature reports. It is observed that small amount of Zr doping on BST, where 0 < x ≤ 0.03 results in the enhancement of dielectric constant while decreasing the bulk density and dielectric loss.