scholarly journals Structural, Electrical, Magnetic and Optical Properties of BaTi1-x(Ni1/2Nb1/2)xO3 Ceramics

2021 ◽  
Author(s):  
sheng li ◽  
yuanyuan zhang ◽  
Lisa Zhou ◽  
Qingqing Liu ◽  
Jing Yang ◽  
...  
Keyword(s):  
Optical Properties ◽  
Room Temperature ◽  
Magnetic Measurement ◽  
Hysteresis Loops ◽  
Solid State Reaction Method ◽  
Conventional Solid State Reaction ◽  
Co Doping ◽  
Nb Doping ◽  
Ferroelectric Hysteresis ◽  
Ferromagnetic Ordering

Abstract In this work, we have investigated the structural, electrical, magnetic and optical properties of Ni-Nb co-doped BaTiO3 ceramics. The compositions of BaTi1 − x(Ni1/2Nb1/2)xO3 were prepared through conventional solid-state reaction method. All the samples exhibit a gradual phase transition behavior from the tetragonal to a cubic structure with the increase of Ni-Nb co-doping concentration. The temperature dependence of the dielectric constant reveals that the transition temperature gradually decreased with an increase in Ni2+ and Nb5+ concentrations. The ferroelectric studies show these doping samples have relatively full ferroelectric hysteresis loops at room temperature, but exhibit a decreasing ferroelectric property with the increasing level of doping. The magnetic measurement suggests that these samples have ferromagnetic ordering at room temperature with an increase in the Ni-Nb doping. Moreover, band gaps of these samples are obviously reduced through the strategy of co-doping.

Room Temperature Magnetoelectric Coupling in Bi5Ti3FeO15 Ceramics

2013 ◽  
Vol 668 ◽  
pp. 762-766 ◽  
Author(s):  
X.Q. Chen ◽  
Xiang Bin Zeng ◽  
F.J. Yang ◽  
X.P. Kong ◽  
C. Wei ◽  
...  
Keyword(s):  
Electric Field ◽  
Room Temperature ◽  
Magnetic Measurement ◽  
Magnetic Hysteresis ◽  
Hysteresis Loops ◽  
Solid State Reaction Method ◽  
Layered Perovskite ◽  
Conventional Solid State Reaction ◽  
Magnetic Dipoles ◽  
Ferroelectric Hysteresis

Magnetoelectric(ME) coupling at room temperature(RT) in four-layered perovskite Bi5Ti3FeO15(BTFO) ceramics prepared by conventional solid state reaction method was observed. Unsaturated ferroelectric hysteresis loop with 2Pr=0.464 μC/cm2 and 2Ec=25 kV/cm at an applied electric field 58 kV/cm was obtained because of lower breakdown voltage which maybe induced by lower relative density of the sample. A weak ferromagnetic (Mr=0.122 memu/g, Hc=69 Oe) rather than an antiferromagnetic property was observed at RT by magnetic measurement. Significantly, the ME coupling between the electric dipoles and magnetic dipoles at RT was demonstrated by measuring the effect of magnetic and DC electric poling on ferroelectric and magnetic hysteresis loops, respectively. Both Pr and Mr decreased after magnetic and DC electric poling. And the rate of Pr change decreased with increasing measuring electric field.

scholarly journals Structure, Dielectric and Multiferroic Properties of Bi0.85Nd0.15Fe0.98Zr0.02O3 in Ba and Ti Co-Doping

2021 ◽  
Author(s):  
Lizhu Zeng ◽  
Yuming Lu ◽  
Lujia Zhang ◽  
Xin Gong ◽  
Jianfeng Tang ◽  
...  
Keyword(s):  
Room Temperature ◽  
Oxygen Vacancies ◽  
Solid State Reaction Method ◽  
X Ray Diffraction ◽  
Conventional Solid State Reaction ◽  
Structure Transition ◽  
X Ray ◽  
Co Doping ◽  
Average Grain Size ◽  
Rhombohedral Perovskite Structure

Abstract Multiferroic (1- x)Bi0.85Nd0.15Fe0.98Zr0.02O3- xBaTiO3 (x = 0, 0.275, 0.3, 0.325, 0.35, 0.375, 0.4) ceramics were synthesized by the conventional solid state reaction method. X-ray diffraction studies confirm the phase transition from rhombohedral perovskite structure to pseudocubic structure with the introduction of BaTiO3. The results of the refinement indicate the BaTiO3 is successfully doped into the crystal lattice. The microstructure analysis shows that the average grain size increases with the introduction of BaTiO3. An increase in remanant polarization has been achieved at room temperature as the BaTiO3 concentration increasing. A greatly reduced leakage current density of about two orders of magnitude is observed in x = 0.375 (J = 2.4×10− 7 A/cm2) ceramic. The dielectric properties have been enhanced by the addition of BaTiO3, which is attributed to the reduction in Fe2+ ions and oxygen vacancies. Due to the grain effect and structure transition caused by the doping of BaTiO3, the magnetization reveals a slight decrease while the coercive field for x = 0.325 (Hc = 1785.8 Oe) increases to 6.4 times of the undoped ceramic.

scholarly journals Effects of sintering temperature and holding time on the microstructure and electric properties of Ba(Zr0.3Ti0.7)O3 ceramics

2018 ◽  
Vol 12 (1) ◽  
pp. 45-55 ◽  
Author(s):  
Xiaoya Zhang ◽  
Gang Chen ◽  
Chunlin Fu ◽  
Wei Cai ◽  
Rongli Gao ◽  
...  
Keyword(s):  
Dielectric Constant ◽  
Room Temperature ◽  
Sintering Temperature ◽  
Perovskite Phase ◽  
Hysteresis Loops ◽  
Holding Time ◽  
X Ray Diffraction ◽  
Conventional Solid State Reaction ◽  
Structure Surface ◽  
Ferroelectric Hysteresis

Ba(Zr0.3Ti0.7)O3 (BZT) ceramics was prepared by using conventional solid state reaction. The effects of sintering temperature and holding time on the crystal structure, surface morphology, dielectric, ferroelectric and piezoelectric properties of the BZT ceramics were systematically investigated. X-ray diffraction (XRD) results confirm single cubic perovskite phase in all the sintered samples. Microstructure analysis using scanning electron microscopy (SEM) reveals that the grain sizes increase with increasing the sintering temperature. Dielectric spectroscopy performed in the range of 20Hz to 2MHz at room temperature shows that the dielectric constant increases with the sintering temperature and the dielectric constant of the BZT ceramics sintered at 1400?C for 8 h is around 11500. The ferroelectric hysteresis loops show that the coercive field decreases with the holding time, while the remnant polarization does not change obviously. The maximum strain is 0.023%for the sample sintered at 1400?C for 4 h. It is found that the maximum value of the direct piezoelectric coefficient (d33) of the BZT ceramics sintered at 1400?C for 8 h measured at room temperature is 36.7 pC/N.

scholarly journals Structural, Morphological and Magnetic Properties of Nd and Co co-doped BiFeO3 Ceramics at Room temperature

2017 ◽  
Vol 41 (1) ◽  
pp. 85-93 ◽  
Author(s):  
Tamanna Mariam ◽  
Shamima Choudhury
Keyword(s):  
Grain Size ◽  
Magnetic Properties ◽  
Room Temperature ◽  
Hysteresis Loops ◽  
Magnetic Behavior ◽  
Solid State Reaction Method ◽  
Conventional Solid State Reaction ◽  
Average Grain Size ◽  
Co Doped ◽  
Simultaneous Substitution

Synthesis and characterization of BiFeO3 samples, co-doped with rare earth Nd and Co in place of Bi and Fe respectively were investigated at room temperature (RT). The formula of the four samples are Co-doped BiFe1–xCoxO3 (x = 0.05-0.10) and Nd and Co co-substituted Bi0.95Nd0.05Fe0.95Co0.05O3 and Bi0.90Nd0.10Fe0.90Co0.10O3. These ceramic samples were synthesized by conventional solid state reaction method. The X-ray diffraction patterns clearly reveal that the secondary impurity phases were eliminated significantly due to the simultaneous substitution of Nd and Co in place of Bi and Fe respectively of BiFeO3 ceramics. The surface morphology of the synthesized samples was found to improve due to the simultaneous substitution of Nd and Co in place of Bi and Fe in BiFeO3. The average grain size of the first sample with 5% doping of Co in place of Fe was 1.5?m. In the second sample with 10% Co doping in place of Fe, the average grain size became 1.25 ?m. In presence of 5% Nd in place of Bi as well as with 5% doping of Co in place of Fe , grain size reduced to 0.75?m. The sample with 10% doping of Nd and Co in place of Bi and Fe respectively, average grain size decreased to 0.5?m. The EDX spectroscpoy ensured the presence of Bi, Nd, Fe, Co and O in these samples and their percentage of mass and atoms. Magnetic properties of the samples were also investigated at room temperature by measuring magnetization versus magnetic field (M-H) hysteresis loops. The wider loop clearly demonstrates the significant improvement of the magnetic behavior in 10% Nd and Co doped Bi0.90Nd0.10Fe0.90Co0.10O3 sample. The enhanced magnetic properties might be attributed to the substitution induced suppression of spiral spin structure of BiFeO3. The outcome of this investigation suggests the potentiality of the simultaneous doping of Nd and Co in BiFeO3 ceramics to improve their structural, morphological and magnetic characteristics.Journal of Bangladesh Academy of Sciences, Vol. 41, No. 1, 85-93, 2017

scholarly journals Crystal structure, dielectric, ferroelectric and energy storage properties of La-doped BaTiO3 semiconducting ceramics

2015 ◽  
Vol 05 (03) ◽  
pp. 1550027 ◽  
Author(s):  
Venkata Sreenivas Puli ◽  
Patrick Li ◽  
Shiva Adireddy ◽  
Douglas B. Chrisey
Keyword(s):  
Energy Storage ◽  
Room Temperature ◽  
Hysteresis Loops ◽  
Electrical Energy ◽  
Solid State Reaction Method ◽  
Positive Temperature Coefficient ◽  
Storage Capacitor ◽  
Positive Temperature ◽  
Conventional Solid State Reaction ◽  
La Doped

Polycrystalline La-doped [Formula: see text] [Formula: see text] [[Formula: see text]] ceramics (denoted as BTO,BLT1,BLT2,BLT3) were synthesized by conventional solid-state reaction method and characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and Raman spectroscopy. XRD and Raman spectra revealed single-phase tetragonal perovskite crystalline structure. Well-saturated polarization–electric field ([Formula: see text]) hysteresis loops were observed with the measurement frequency of 50 Hz at room temperature and confirmed ferroelectric nature of these ceramics and a high recoverable electrical energy storage density of 0.350 J/cm3 with energy efficiency [Formula: see text], which is useful in energy storage capacitor applications. Dielectric studies revealed anomalies around 415–420 K and near the Curie temperature. The latter is attributed to the ferroelectric to paraelectric phase transition. Better dielectric performances were obtained for La-doped samples sintered at 1350°C for 4 h. Grain growth is inhibited with lanthanum (La) incorporation into the BTO lattice. Room temperature semiconducting behavior with positive temperature coefficient of resistivity (PTCR) behavior at [Formula: see text] is attributed to electron compensation mechanism.

scholarly journals Influence of CuO addition on dielectric and piezoelectric properties of (Bi0.5Na0.5)TiO3–BaTiO3lead-free piezoceramics

2021 ◽  
pp. 2140004
Author(s):  
M. Difeo ◽  
L. Ramajo ◽  
M. Castro
Keyword(s):  
Hysteresis Loops ◽  
Solid State Reaction Method ◽  
Sem Analysis ◽  
Sintering Behavior ◽  
X Ray Diffraction ◽  
Conventional Solid State Reaction ◽  
Doping Effects ◽  
Density Values ◽  
Spectroscopy Studies ◽  
Ferroelectric Hysteresis

Doping effects of CuO on the sintering behavior and electrical properties of 0.94(Bi[Formula: see text]Na[Formula: see text]TiO3–0.06(BaTiO[Formula: see text]–[Formula: see text]CuO (BNT–BT6–[Formula: see text]Cu) lead-free piezoceramic obtained by the conventional solid-state reaction method were investigated. Regarding the undoped system, it is already known that it presents the best densification values when it is sintered at 1150[Formula: see text]C, however, the doped system was sintered at 1150[Formula: see text]C, 1100[Formula: see text]C, 1050[Formula: see text]C, 1025[Formula: see text]C, and 975[Formula: see text]C to determine the effect of Cu on the densification process. Therefore, it was obtained that the CuO-doped samples sintered at 1050[Formula: see text]C presented the highest density values and therefore were the ones chosen to perform the characterization tests together with the undoped system. The samples were characterized using X-ray diffraction (XRD), Raman microspectroscopy, and scanning electron microscopy (SEM) analysis, whereas the ferroelectric and dielectric properties were evaluated by means of ferroelectric hysteresis loops and impedance spectroscopy studies. As a result, the addition of CuO allowed an improvement in sinterability and densification, with the subsequent grain growth, and the improvement of the piezoelectric coefficient ([Formula: see text].

Investigations of PbxSr1-xTiO3 Thin Films and Ceramics for Microelectronic Applications

2004 ◽  
Vol 811 ◽  
Author(s):  
M. Jain ◽  
Yu.I. Yuzyuk ◽  
R.S. Katiyar ◽  
Y. Somiya ◽  
A.S. Bhalla ◽  
...  
Keyword(s):  
Thin Films ◽  
Phase Transition ◽  
Room Temperature ◽  
Sol Gel ◽  
Solid State Reaction Method ◽  
Phase Shifters ◽  
Conventional Solid State Reaction ◽  
Mode Behavior ◽  
Dielectric Devices ◽  
Pst System

ABSTRACTWe have investigated electrical and optical properties of the lead strontium titanate {(PbxSr1-x)TiO3 or PST} ceramic and dielectric properties of the thin films of PST at low and high frequencies. (PbxSr1-x)TiO3 compositions with × ≤ 0.4 are paraelectric at room temperature and exhibit ferroelectric phase transition below room temperature. Only one phase transition in the PST system (compared to three in BaxSr1-xTiO3) was recorded. The studies indicated that PST has potential for tunable microwave devices in the paraelectric phase. In the present studies, Pb0.3Sr0.7TiO3 (PST30) ceramic was prepared by the conventional solid-state reaction method and thin films of PST were prepared by sol-gel technique. Structural, microstructural, dielectric, and Raman measurements were performed on these samples. Sharp phase transition was observed in case of the ceramic by dielectric and Raman measurements at 283 K. Raman measurements revealed well-pronounced soft-mode behavior below the Curie temperature in PST ceramic. The thin film of PST deposited on lanthanum aluminate substrate was highly (100) oriented and showed dielectric maxima at ∼280 K, which was close to that in case of the bulk. Eight element coupled micro-strip phase shifters (CMPS) was fabricated on the PST film and tested in the frequency range of 15-17 GHz. The average figure of merit of 49 °/dB for PST30 film in the Ku band at 533 kV/cm suggests the potentiality of these films for high frequency tunable dielectric devices.

Effect of Gd Substitution on the Dielectric Properties and Magnetoelectric Effect of BiFeO3

2010 ◽  
Vol 150-151 ◽  
pp. 1470-1475
Author(s):  
Gui Lin Song ◽  
Tian Xing Wang ◽  
Cun Jun Xia ◽  
Chao Li ◽  
Fang Gao Chang
Keyword(s):  
Dielectric Constant ◽  
Rare Earth ◽  
Dielectric Loss ◽  
Room Temperature ◽  
Magnetoelectric Effect ◽  
Solid State Reaction Method ◽  
Impurity Phase ◽  
Conventional Solid State Reaction ◽  
Reaction Method ◽  
Dielectric Relaxation Process

Multiferroic Bi1-xGdxFeO3(x=0, 0.05, 0.1, 0.15, 0.2) ceramics were prepared by conventional solid state reaction method. For all the samples prepared, they exhibit magnetoelectric effect at room temperature, and the dielectric constant and dielectric loss decrease with increasing frequency in the range from 10000Hz to 1 MHz from a typical orientational dielectric relaxation process. It has been found that both dielectric constant and dielectric loss are strongly dependent on the Gd3+ content. And substitution of Bi with rare earth Gd helps to eliminate the impurity phase in BiFeO3 ceramics.,

Investigation of Optical Properties of ZnO/MnO2, ZnO/TiO2 and ZnO/MnO2/TiO2 Nanocomposites

2014 ◽  
Vol 938 ◽  
pp. 123-127 ◽  
Author(s):  
G. Shanmuganathan ◽  
I.B. Shameem Banu
Keyword(s):  
Optical Properties ◽  
Room Temperature ◽  
Optical Band Gap ◽  
Energy Gap ◽  
Visible Region ◽  
Solid State Reaction Method ◽  
Morphological Properties ◽  
Energy Dispersive Analysis ◽  
Reaction Method ◽  
Uv Visible

ZnO nanocomposites such as (ZnO)0.8(MnO2)0.2, (ZnO)0.8(TiO2)0.2and (ZnO)0.8(MnO2)0.1(TiO2)0.1were prepared by solid state reaction method at room temperature. The structural analysis was carried out with help of powder XRD to confirm the formation of the composites. The morphological properties and presence of elemental compositions were analyzed with scanning electron microscope and energy dispersive analysis spectroscopy respectively. Optical properties were studied with UV visible spectrophotometer. From the transmittance spectrum, it is concluded that the synthesized composite materials have the transmittance in the range of 80 to 95% in the visible region. The calculated optical band gap values for pure ZnO is 3.16 eV and the values are 3.7eV, 5.27eV and 4.46eV for the composites ZnO/MnO2, ZnO/TiO2and ZnO/MnO2/TiO2, respectively. The study has found that the ZnO/MnO2, ZnO/TiO2and ZnO/MnO2/TiO2composites have very large energy gap as that of insulator.

Dielectric, ferroelectric, and ferromagnetic properties of 0.7Bi1−xLax(Fe0.9Cr0.1)O3–0.1BaTiO3–0.2PbTiO3 solid solutions

2010 ◽  
Vol 25 (9) ◽  
pp. 1812-1816 ◽  
Author(s):  
Xiao-hui Liu ◽  
Zhuo Xu ◽  
Xiao-yong Wei ◽  
Xi Yao
Keyword(s):  
Solid Solutions ◽  
Room Temperature ◽  
Hysteresis Loops ◽  
Weak Ferromagnetism ◽  
Lattice Parameter ◽  
X Ray Diffraction ◽  
Crystal Lattices ◽  
Temperature Polarization ◽  
Polarization Electric Field ◽  
Ferroelectric Hysteresis

Solid solutions 0.7Bi1−xLax (Fe0.9Cr0.1) O3–0.1BaTiO3–0.2PbTiO3 (BLxFOC-BT-PT, with x = 0, 0.03, 0.05, 0.07) solid solutions were prepared by the traditional ceramic process. X-ray diffraction results reveal that all samples show pure pseudocubic perovskites structure. The lattice parameter of the solid solutions increases linearly with the La content, indicating that La ions have entered crystal lattices to form a solid solution. The Curie temperature of the solid solutions decreases with the La content. Room-temperature polarization–electric field (P–E) curves indicate that the samples with x = 0.03 and 0.05 exhibit saturated P–E loops. Piezoelectric constant d33 of the solid solutions increases firstly and then decreases. Magnetizations of the solid solutions decrease with the La content. The evidence of weak ferromagnetism and saturated ferroelectric hysteresis loops in BLxFOC–BT–PT system at room temperature makes it a good candidate for multiferroic applications.

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