Electrical Properties Of Bi Research Articles

Effect the Partial Substitution of (Pb, Ag) on Structural and Electrical Properties of Bi<SUB>2</SUB>Sr<SUB>2</SUB>Ca<SUB>2</SUB>Cu<SUB>3</SUB>O<SUB>10+δ</SUB> High Temperature Superconductor

This research involved the preparation of samples of Bi2-(x+y)PbxAgy Sr2Ca2Cu3O10+δ compounds and with different concentration of (x,y) which are (x=y=0) (x=0.05,y=0.15) (x=y=0.1) (x=0.15, y=0.05) by the method of solid state reaction under hydrostatic pressure of 8 ton/cm2 temperature of annealing 850 k to know the range of effect of partial substitution on the synthetic and electric properties of compound. After undergoing the test of x-ray diffraction, it looked like the best substitution ratio of pb and Ag in Bi is when (x=0.05,y=0.15 ) where the values of lattice dimensions were a=b=5.4056 c=37.4226 A◦ and the crystalline composite is of tetragonal type this research also revealed that the oxygen has a vital role in increasing the critical temperature, we noticed by studying the electrical properties the critical temperature in this substitution Tc=143 k.

Structural and electrical properties of Bi(Mg0.5Ti0.5)O3 ceramic

Bismuth magnesium titanate Bi(Mg0.5Ti0.5)O3 ceramic, fabricated by ceramic processing technique, has been characterized using various experimental techniques. Analysis of basic crystal structure using X-ray diffraction data has exhibited the orthorhombic system as a major phase. Microstructural analysis provided the quality of the sample. Detailed studies of electrical properties (dielectric constant, tangent loss, electrical modulus, conductivity and impedance) of Bi(Mg0.5Ti0.5)O3 in a wide range of frequency (1 kHz–1 MHz) and temperature (25–480 °C) have provided various interesting results on antiferroelectric characteristics, conduction mechanism, structure–properties relationship, etc. An important role of interface in getting high dielectric material has been realized. The space charge polarization and Maxwell–Wagner dielectric relaxation in the material, particularly at low frequencies and high temperatures. Nyquist plots discuss the temperature-dependent contributions of grain effect. The frequency of the applied electric field and temperature strongly affect the electrical (AC) conductivity and transport properties of the material studied, and exhibiting semiconductor characteristics.

Structural, dielectric and impedance study of Bi and Li co-substituted Ba0.50Sr0.50TiO3 ceramics for tunable microwave devices applications

In this article, the structural, dielectric and electrical properties of Bi and Li co-substituted (Ba, Sr) site in Ba0.50Sr0.50TiO3 ceramics are presented. Four different compositions of Ba0.50Sr0.50TiO3, (Ba0.50Sr0.50)0.98(Bi, Li)0.02TiO3, (Ba0.50Sr0.50)0.96(Bi, Li)0.04TiO3, and (Ba0.50Sr0.50)0.92(Bi, Li)0.08TiO3 were synthesized using solid-state reaction with microwave heating of starting materials. Phase detection for all samples has been examined by XRD along with Rietveld refinement analyses, and the results show the formation of single phase without observation of any secondary phase. However, a decrease in crystallite size, lattice parameters, and unit cell volume has been observed with the increase of Bi and Li concentration. A Dense microstructure with different grains sizes and shapes has been obtained by scanning electron microscopy. Impedance spectroscopy in the temperature range of 30–300 °C and frequency range of 60 Hz–1 MHz has been used to study the dielectric properties. The result shows that the Bi and Li co-substituted Ba0.5Sr0.5TiO3 ceramics exhibit very interesting features, such as enhanced dielectric constant with low loss which make it suitable for microwave tunable devices applications. An electric impedance analysis was carried out at different temperatures namely (400, 450, 500, and 550 °C). A single semicircular arc with single relaxation process has been observed in all studied samples which suggest that the grains contribute to the total resistance in these materials. The activation energy was obtained from the impedance analysis using Arrhenius plot of grain conductivity.

Erratum to: Effect of Hf and Li on the structure and electrical properties of Bi0.5Na0.5TiO3 lead-free ceramics

Lead-free (Bi0.5Na0.5−y Li y )(Ti1−x Hf x )O3 piezoelectric ceramics were prepared using a conventional solid-state method, and the effects of Li and Hf on phase structure and electrical properties were systematically investigated. All the ceramics exhibited a rhombohedral phase, which is independent on the doped Li and Hf elements and contents. With the increase of Hf4+ or Li+, their T d values gradually decreased. Their piezoelectric and dielectric properties can be effectively enhanced by optimizing the amount of Hf4+ and Li+, and maximum d 33 value of ~100 pC/N and e r value of ~850 were achieved for x = 0.03, y = 0.1 and x = 0.12, y = 0, respectively. In addition, it was found that the ferroelectric and strain behavior was gradually weakened with the addition of Li and Hf. This research helps understand the influence of Li and Hf on the structure and properties of bismuth sodium titanate materials.

Effect of Hf and Li on the structure and electrical properties of Bi0.5Na0.5TiO3 lead-free ceramics

Effect of Hf and Li on the structure and electrical properties of Bi0.5Na0.5TiO3 lead-free ceramics

Microstructural and Electrical Properties of Bi0.9A0.1Fe0.975V0.025O3+α (A=Nd, Tb) Thin Films by Chemical Solution Deposition Method

Microstructural and Electrical Properties of Bi0.9A0.1Fe0.975V0.025O3+α (A=Nd, Tb) Thin Films by Chemical Solution Deposition Method

Improvement of nucleation and electrical properties of Bi3.15Nd0.85Ti2.99Mn0.01O12 thin films with an upper Bi4Ti3O12 buffer layer

A highly (117)-preferred Bi3.15Nd0.85Ti2.99Mn0.01O12 (BNTM) thin film with an upper Bi4Ti3O12 (BTO) buffer layer was fabricated on Pt(111)/Ti/SiO2/Si(100) substrates by a sol–gel method. The effects of the added upper Bi4Ti3O12 (BTO) layer on the structural and electrical properties of BNTM were investigated. X-ray diffraction, SEM and AFM images indicated that BTO/BNTM thin films exhibited a significantly higher (117) orientation and larger grain growth compared with the BNTM thin films (without the upper BTO layer). It was found that the BTO/BNTM thin films further showed the relatively larger remanent polarization (2P r = 94.3 μC/cm2) and dielectric constant (e r = 467.8). The enhancement of piezoelectric properties was also obtained in BTO/BNTM thin films. Moreover, the BTO/BNTM thin films displayed the better fatigue properties, degraded by only 7.4 % after 109 pulse cycles as compared to 30.2 % for BNTM thin films. A highly (117)-preferred Bi3.15Nd0.85Ti2.99Mn0.01O12 (BNTM) thin film with an upper Bi4Ti3O12 (BTO) buffer layer was fabricated on Pt(111)/Ti/SiO2/Si(100) substrates by a sol–gel method. The effects of the added upper Bi4Ti3O12 (BTO) layer on the structural and electrical properties of BNTM were investigated. X-ray diffraction, SEM and AFM images indicated that BTO/BNTM thin films exhibited a significantly higher (117) orientation and larger grain growth compared with the BNTM thin films (without the upper BTO layer). It was found that BTO/BNTM thin films further showed the relatively larger remanent polarization (2P r = 94.3 μC/cm2) and dielectric constant (e r = 467.8). The enhancement of piezoelectric properties was also obtained in BTO/BNTM thin films. Moreover, the BTO/BNTM thin films displayed the better fatigue properties, degraded by only 7.4 % after 109 pulse cycles as compared to 30.2 % for BNTM thin films.

Phase transition and electrical properties of Bi0.5(Na0.8K0.2)0.5ZrO3 modified (K0.52Na0.48)(Nb0.95Sb0.05)O3 lead-free piezoelectric ceramics

In this work, (1−x)(K0.52Na0.48)Nb0.95Sb0.05O3−xBi0.5(Na0.8K0.2)0.5ZrO3 [abbreviated as (1−x)KNNS−xBNKZ, x=0–0.06] lead-free ceramics were fabricated using solid-state reaction method. The effects of BNKZ contents on the phase structure, piezoelectric and ferroelectric properties were investigated. The phase boundaries including orthorhombic-tetragonal (O-T) and rhombohedral-tetragonal (R-T) multiphase coexistence were identified by XRD patterns and temperature-dependent dielectric constant by adding different content of BNKZ. A giant field induced strain (~0.25%) along with converse piezoelectric coefficient d33* (~629.4pm/V) and enhanced ferroelectricity Pr (~38μC/cm2) were obtained when x=0.02, while the specimen with x=0.03 presented the optimal piezoelectric coefficient d33 of 215pC/N, due to the O-T or R-T phase coexistence near room temperature respectively. These results show that the introduction of Bi0.5(Na0.8K0.2)0.5ZrO3 is a very effective way to improve the electrical properties of (K0.52Na0.48)(Nb0.95Sb0.05)O3 lead-free piezoelectric ceramics.

Hybridization between microstructure and magnetization improvement in lead and RE co-doped BiFeO3

The crystal structure, magnetic and electrical properties of Bi0.96Pb0.04FeO3 and Bi0.92Pb0.04 RE0.04FeO3 (RE=La, Sm, Dy and Yb) polycrystalline samples were prepared by the flash autocombustion technique. X-ray diffraction (XRD) measurements show that the rare-earth doped compositions crystallized in rhombohedral symmetry of space group R3c. The undoped sample consisted needle shape particles while rare earth substitution preferred platelet like particles as clarified from high resolution transmission electron microscopy (HRTEM). Morphological features were examined using field emission scanning electron microscopy (FESEM). Magnetization measurements showed that Yb3+ samples possessed the highest room temperature saturation magnetization while when Bi3+ ions were substituted by La3+ ions, a smaller MS (0.28 emu/g) was obtained. The coexistence of ferroelectric and magnetic transitions was detected using DSC and χM, indicating the multiferroic characteristics of Bi0.92Pb0.04RE0.04FeO3 crystallites. The Néel temperature shifted upwards with decreasing the ionic radius of rare earth ion. Nice correlation was established between microstructure, morphology and magnetic properties in view of the contribution of magnetocrystalline and shape anisotropy in the magnetic parameters values.

Correlation between the microstructure and electrical properties of Bi–As2S3 quasibinar chalcogenides by using AC impedance spectroscopy

The objective of this paper was to study the AC impedance of Bi5(As2S3)95 and Bi7(As2S3)93 chalcogenides in a frequency range of 100 Hz to 1 MHz at different temperatures. A preliminary structural analysis of the compounds by X-ray diffraction technique and scanning electron microscope confirmed the amorphous character for the sample with x = 5 at.% Bi and the existence of two phases (amorphous + crystalline) for the sample with x = 7 at.%. Therefore, the AC impedance analysis by means of an equivalent circuit model was used to establish correlation between the distinct microstructures and electrical properties of these compounds. The presence of the glassy matrix and matrix–crystal interface effects was observed in the sample Bi7(As2S3)93. Moreover, the analysis of impedance data indicated the decrease of resistance with temperature for both samples usually shown by semiconductors i.e. negative temperature coefficient of resistance. The present Bi–As2S3 quasibinar chalcogenides also exhibit the temperature dependent relaxation phenomena. According to estimated values of activation energy of relaxation processes, it was concluded that the mechanisms of conductivity and relaxation are the same in both samples.

Structural and Electrical Properties of Bi$_{0.5}$Na$_{0.5}$TiO$_3$ Templates Produced by Topochemical Microcrystal Conversion Method

Structural and Electrical Properties of Bi$_{0.5}$Na$_{0.5}$TiO$_3$ Templates Produced by Topochemical Microcrystal Conversion Method

Effects of Bi2O3, TiO2, and Bi4Ti3O12 Seeding Layers on the Structural and Electrical Properties of Bi3.25La0.75Ti3O12 Thin Films Grown by a Sol–Gel Method

Ferroelectric Bi3.25La0.75Ti3O12 (BLT) thin films with Bi2O3, TiO2, and Bi4 Ti3O12 (BTO) seeding layers were prepared on Pt/TiO2/SiO2/Si (100) substrate by a sol–gel technique. The effects of the different seeding layers on the structural and electrical properties of the BLT films were investigated. X-ray diffraction indicated that the predominant orientation of the BLT thin film on the BTO seeding layer was (117). Growth of films with the Pt/BLT/Bi2O3/Pt structure was oriented differently from that of films with the Pt/BLT/TiO2/Pt and Pt/BLT/Pt structures. In addition, in comparison with the BLT film deposited directly on Pt, the TiO2 layer substantially enhanced the leakage current resistance of the BLT film. The ferroelectric nature of the BLT thin film was substantially improved by use of a BTO seeding layer. In an applied field of 750 kV/cm, the remnant polarization (2P r) of the Pt/BLT/BTO/Pt capacitor was 61.5 μC/cm2. After 1010 switching cycles, 2P r of the BLT, BLT/Bi2O3, BLT/TiO2, and BLT/BTO films was degraded by approximately 13, 11, 1, and 2%, respectively, indicating that all the capacitors with the different seeding layers had good polarization fatigue characteristics.

Enhanced Electrical Properties of Bi0.9Gd0.1Fe0.975B0.025O3±δ, (B = Ni, Mn, Cu, Ti, and V) Thin Films

Pure BiFeO3 (BFO) and Gd-transition metal co-doped (Bi0.9Gd0.1)(Fe0.975B0.025)O3±δ (B = Ni, Mn, Cu, Ti, and V, denoted by BGdFNi, BGdFMn, BGdFCu, BGdFTi, and BGdFV) films were deposited by using a chemical solution deposition. Enhanced electrical properties were observed for the co-doped films. The BGdFMn film showed the largest 2Pr value (105.3 μC/cm2 at 1470 kV/cm) and the smallest leakage current density (1.49 × 10−5 A/cm2 at 100 kV/cm). The enhanced electrical properties for the co-doped films are related to the decrease of oxygen vacancies, the stabilization of perovskite structure, and the lattice distortion by the doping elements.

Influence of Bi<sub>3.15</sub>Nd<sub>0.85</sub>Ti<sub>3</sub>O<sub>12</sub> Buffer Layer on Structure and Electrical Properties of Bi<sub>0.94</sub>Ce<sub>0.06</sub>Fe<sub>0.97</sub>Ti<sub>0.03</sub>O<sub>3</sub> Thin Films

Bi0.94Ce0.06Fe0.97Ti0.03O3 and Bi0.94Ce0.06Fe0.97Ti0.03O3/Bi3.15Nd0.85Ti3O12 double-layered thin films were fabricated via sol-gel process on Pt/Ti/SiO2/Si substrates. The influence of Bi3.15Nd0.85Ti3O12 buffer layer on microstructure and electrical properties of Bi0.94Ce0.06Fe0.97Ti0.03O3 thin films were investigated in detail. Well-saturated P-E hysteresis loops can be obtained in Bi0.94Ce0.06Fe0.97Ti0.03O3 films with Bi3.15Nd0.85Ti3O12 buffer. The remnant polarization (2Pr) of the double-layered thin films is 112 μC/cm2. The coercive field (2Ec) of double-layered films is 672 kV/cm, which is much lower than that of the Bi0.94Ce0.06Fe0.97Ti0.03O3 thin films. The leakage current density of Bi0.94Ce0.06Fe0.97Ti0.03O3/Bi3.15Nd0.85Ti3O12 double-layered thin films is 4.12×10-5 A/cm2.

Structural and electrical properties of Bi0.5Na0.5 TiO3 based superlattices grown by pulsed laser deposition

Artificial superlattices of ferroelectric Bi0.5Na0.5TiO3 and BaTiO3 have been successfully grown on (001) insulator or conductive SrTiO3 substrates by pulsed laser deposition. In these epitaxial layered structures, the BaTiO3 layers were shown to contribute to an improvement of the two dimensional growth of the Bi0.5Na0.5TiO3 layers. The influence of the superlattice period Λ, between 5 and 20 nm, was investigated. We observe an increase in the in-plane tensile strain as Λ is reduced from 20 nm to 10 nm, accompanied by a decrease in the density of dislocations. A concomitant enhancement of the dielectric permittivity was measured, demonstrating the strain tunability of these superlattices. A significant reduction of the dielectric losses is also obtained with decreasing Λ. Furthermore, a minimum value of the coercive field of less than 70 kV/cm, close to that of Bi0.5Na0.5TiO3 bulk ceramics, was reached by decreasing the period. We demonstrate that the dielectric and ferroelectric properties can be explained as the result of the in-plane tensile strain which contributes to improve the structural properties in the superlattices.

A comparative study on the magnetic and electrical properties of Bi0.89Tb0.11FeO3 and Bi0.89Tb0.11FeO3/CoFe2O4 multiferroic thin films

A double layered multiferroic thin film consisting of Bi0.89Tb0.11FeO3 (BTFO) and CoFe2O4 (CFO) layers has been deposited on a FTO/glass substrate by the chemical solution deposition method. The influence of magnetic layer on the crystal structure, dielectric, ferroelectric and magnetic properties of the double layered film was investigated. X-ray diffraction, Raman spectra and scanning electron microscope results demonstrate the perfect formation of double layered thin film structure without second phase. With the introduction CFO magnetic layer, the double layered film of dielectric constant shows strong frequency dependence, and the leakage current density and the multiferroic properties have been significantly improved. It is believed that at room temperature the superior multiferroic parameters (2Pr∼218μC/cm2 and 2Mr∼100.9emu/cm3) of the BTFO/CFO film are a major breakthrough in the double layered BFO-based films. The double layered film with excellent multiferroic properties become an attractive research focus in potential multifunctional devices.

Effect of excess Bi content on the electrical properties of Bi0.95La0.05FeO3 thick films

BiFeO3 (BFO)-based ferroelectric films thicker than 1 µm are promising in dielectric, piezoelectric, and pyroelectric applications. However, using the common sol–gel technology to prepare BFO-based thick films is difficult because of crack formation and poor crystallization. In this study, we demonstrate that it is possible to prepare well-crystallized Bi0.95La0.05FeO3 (BLFO) thick films with a thickness of 1.4 µm by modifying excess Bi content. The effect of excess Bi content on the electrical properties of the BLFO thick film was investigated. Most excess Bi particles were found to be concentrated in the grain boundaries of thick films instead of volatilizing. Adding appropriate excess Bi when preparing BLFO thick films was also found to promote crystal growth and improve electrical properties.

Structure and Electrical Properties of Bi0.5Na0.5TiO3 0-3 Composite Lead-Free Thick Films

The use of piezoelectric films in high-frequency ultrasonic transducers requires thick, dense, and crack-free films with excellent piezoelectric properties. In this work, Bi0.5Na0.5TiO3 (abbreviated to BNT) 0-3 composite lead-free ferroelectric thick films have been successfully prepared by a modified 0-3 composite technique. The BNT fine ceramic powders were dispersed in a sol-gel solution of the same composition to form a uniform slurry, which was deposited on (111) Pt/TiO2/SiO2/Si substrates using spin-coating and then annealed at 700°C. The morphology, microstructure, dielectric properties, ferroelectric properties and leakage current densities of BNT composite thick films have been investigated. BNT ceramic powders sintered at a series of temperatures were used to prepare the thick films. X-ray diffraction analysis indicates that the BNT 0-3 composite thick films exhibit a pure perovskite structure. The electrical properties of the composite films depend strongly on the sintering temperature of BNT ceramic powders.

Electromechanical and electrical properties of Bi0.5Na0.5Ti1−xMnxO3−δ ceramics with high remnant polarization

The perovskite oxides Bi0.5Na0.5Ti1−xMnxO3−δ (BNTM10000x, x=0%, 0.25%, 0.5%, 0.75%, 1%, 1.5%, 2%) were prepared via the conventional solid state reaction method. The crystal structure of BNT and BNTM25 ceramics were refined by the Rietveld method with powder X-ray diffraction at room temperature. A production of small amount of oxygen vacancies, a significant enhancement in tetragonality and a grain size effect due to the MnO2 doping, led to the enhancements of the electromechanical and electrical properties of Bi0.5Na0.5Ti1−xMnxO3−δ ceramics, and the optimized modification was x=0.25%. The electrical properties of modified samples were deteriorated with further doping (x=0.5–2%), owing to an obvious ferroelectric to relaxor phase transition and an increase in the concentration of oxygen vacancies. The BNTM25 ceramics was found to have a high remnant polarization (Pr) of 48.5μC/cm2, an electromechanical coupling factor (kp) of 0.18, an electro-field-induced strain (Stotal) of 0.24% and a piezoelectric coefficient (d33) of 105pC/N. In addition, almost no profound fatigue was observed after switching over 106 cycles at room temperature, indicating a potential application as lead-free piezoelectric materials.

Effect of BiMeO3 on the Phase Structure, Ferroelectric Stability, and Properties of Lead‐Free Bi0.5(Na0.80K0.20)0.5TiO3 Ceramics

The effects of BiMeO3 (Me = Fe, Sc, Mn, Al) addition on the phase transition and electrical properties of Bi0.5(Na0.80K0.20)0.5TiO3 (BNKT20) lead‐free piezoceramics were systematically investigated. Results showed that addition of BiFeO3 into BNKT20 induces a phase transition from tetragonal–rhombohedral coexisted phases to a tetragonal phase with the observation of enhanced piezoelectric properties (d33 = 150 pC/N for 0.02BiFeO3). BiScO3, BiMnO3, and BiAlO3 substitutions into BNKT20 induce a phase transition from coexistence of ferroelectric tetragonal and rhombohedral to a relaxor pseudocubic with a significant disruption of the long‐range ferroelectric order, and correspondingly adjusts the ferroelectric–relaxor transition point TF–R to room temperature. Accordingly, large accompanying normalized strains of 0.34%–0.36% are obtained near the ferroelectric–relaxor phase boundary, and the mergence of large strain response can be ascribed to a reversible field‐induced ergodic relaxor‐to‐ferroelectric phase transformation. Moreover, our study also revealed that the composition located at the ferroelectric–relaxor phase boundary where the strain response is consistently derivable shifts to a BNKT20‐rich composition as the tolerance factor t of the end‐member BiMeO3 increases, and this relationship is expected to provide a guideline for designing high‐performance (Bi0.5Na0.5)TiO3‐based materials by searching the ferroelectric–relaxor phase boundary.