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.

Electrical Properties of Nb-Doped and Nb-Mn-Codoped BaTiO3-(Bi0.5Na0.5)TiO3 Lead-Free PTCR Ceramics

2010 ◽  
Vol 67 ◽  
pp. 134-142
Author(s):  
Guo Rong Li ◽  
Sen Lin Leng ◽  
Liao Ying Zheng ◽  
Jiang Tao Zeng ◽  
Zhi Jun Xu ◽  
...  
Keyword(s):  
Room Temperature ◽  
Solid State Reaction Method ◽  
Positive Temperature Coefficient ◽  
Lead Free ◽  
High Resistivity ◽  
Room Temperature Resistivity ◽  
Positive Temperature ◽  
Conventional Solid State Reaction ◽  
Xrd Patterns ◽  
Temperature Resistivity

Nb-doped and Nb-Mn-codoped (1-xmol%)BaTiO3-xmol%(Bi0.5Na0.5)TiO3 (BBNTx) lead-free positive temperature coefficient of resistivity (PTCR) ceramics were prepared by the conventional solid state reaction method. The XRD patterns indicated that all BBNTx samples formed a single perovskite structure with tetragonal phase. 0.25 mol% Nb doped BBNT1 ceramic, sintered at 1330°C for 1h in air, had low room-temperature resistivity (ρ25) of 80 Ω•cm and a high resistivity jump (maximum resistivity [ρmax]/minimum resistivity [ρmin]) of 4.2 orders of magnitude with Tc about 152°C. The Nb-doped BBNTx (10≤x≤60) ceramics also showed distinct PTC effect with Tc between 185 and 232°C by sintering in N2, which was shut off when samples were cooled to a low temperature. In addition, The Nb-Mn-codoped BBNT1 ceramics exhibited higher resistivity jump than the single Nb-doped ones, with increasing the room-temperature resistivity.

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.

Fabrication of Lead-Free and High Tc Positive Temperature Coefficient of Resistivity Ceramics Sintered in Air

2011 ◽  
Vol 415-417 ◽  
pp. 1005-1008
Author(s):  
Jun Zhao ◽  
Hai Bo Yang ◽  
Shu Ping Gong ◽  
Dong Xiang Zhou
Keyword(s):  
Temperature Coefficient ◽  
Solid State Reaction Method ◽  
Positive Temperature Coefficient ◽  
Lead Free ◽  
Room Temperature Resistivity ◽  
Positive Temperature ◽  
Conventional Solid State Reaction ◽  
High Tc ◽  
C Value ◽  
Temperature Coefficient Of Resistivity

As a lead-free positive temperature coefficient of resistivity (PTCR) material, [Ba0.95-x (K0.5Bi0.5)0.05Cax]1-yNbyO3 system was prepared by the conventional solid-state reaction method. All samples sintered in air at 1300°C possess PTC characteristics as well as semi-conductivity characteristics, especially they show high Tc(130°C~160°C) value and the jump of the resistivity (maximum resistivity ρmax / minimum resistivity ρmin ) is four orders of magnitude. Samples with the composition of 0.3mol% Nb5+ have low room-temperature resistivity (ρ25°C) of ~103Ω.cm.

scholarly journals Study the structural and magnetic properties of rare-earth ions (La and Gd) doped Ba0.9575Ca0.0025Ti0.80685Mn0.002475Nb0.002475Zr0.1782O3 (BCTMNZ) ceramics

2015 ◽  
Vol 05 (04) ◽  
pp. 1520001 ◽  
Author(s):  
Radheshyam Rai ◽  
Poonam Kumari ◽  
M. A. Valente
Keyword(s):  
Magnetic Properties ◽  
Rare Earth ◽  
Hysteresis Loops ◽  
Solid State Reaction Method ◽  
Rare Earth Ions ◽  
Temperature Hysteresis ◽  
X Ray Diffraction ◽  
Conventional Solid State Reaction ◽  
Structural And Magnetic Properties ◽  
La Doped

In this paper, we investigated the influence of rare earth ([Formula: see text] and Gd) doped Ba[Formula: see text]RE[Formula: see text]Ca[Formula: see text]Ti[Formula: see text] Mn[Formula: see text]Nb[Formula: see text]Zr[Formula: see text]O3 (BCTMNZ) ceramics were fabricated by using a conventional solid-state reaction method. The doping effects of La and Gd on the structural and magnetic properties were studied. The structural pattern of the ceramic samples were investigated by X-ray diffraction and the results indicated that both samples shows an orthorhombic structure with pure phase. Strain and crystalline size values for Gd and La doped were 0.31–0.33% and [Formula: see text]–[Formula: see text]m, respectively. The room temperature hysteresis loops were obtained by using a vibrating sample magnetometer. La doped ceramic showed the higher value of magnetization i.e., [Formula: see text]B/f.u. as compared to Gd doped BLTMNZ ceramics.

Electrical and thermal properties of a (Ba1-x-ySrxCay)TiO3-based PTC thermistor for preheating light oil

2018 ◽  
Vol 11 (05) ◽  
pp. 1850076 ◽  
Author(s):  
Joonsoo Kim
Keyword(s):  
Thermal Properties ◽  
Electrical Properties ◽  
Solid State Reaction Method ◽  
Positive Temperature Coefficient ◽  
Room Temperature Resistivity ◽  
Positive Temperature ◽  
Conventional Solid State Reaction ◽  
Heater Element ◽  
Light Oil ◽  
Cartridge Heater

The electrical properties of a (Ba[Formula: see text]SrxCay)TiO3-based positive temperature coefficient (PTC) thermistor were determined by measuring resistivity with increasing temperature, and its thermal properties were measured with a cartridge heater made of a (Ba[Formula: see text]Sr[Formula: see text]Ca[Formula: see text])TiO3-based PTC thermistor. The (Ba[Formula: see text]SrxCay)TiO3-based PTC thermistor were fabricated by a conventional solid-state reaction method with Sb2O3, BaTiO3, SrTiO3, SiO2, and CaTiO3. Their electrical properties were determined by room temperature resistivity ([Formula: see text]C), minimum resistivity ([Formula: see text]), maximum resistivity ([Formula: see text]), resistivity jump rate (log [Formula: see text]/[Formula: see text]), Curie temperature ([Formula: see text]), and withstanding voltage. The effect of the microstructure on the electrical properties was investigated to improve the withstand voltage. The cartridge heater was fabricated with the (Ba[Formula: see text]Sr[Formula: see text]Ca[Formula: see text])TiO3-based PTC thermistor and its thermal properties were determined by the temperature of light oil in a 100 cc beaker. The temperature of light oil was maintained at 60[Formula: see text]C without fluctuations in temperature after reaching 60[Formula: see text]C at 220[Formula: see text]V, and thus (Ba[Formula: see text]SrxCay)TiO3-based PTC thermistor was able to operate as a self-regulating heater element for preheating light oil.

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

PTC Behavior and Microstructure of Zn-Ni-Ti-O Ceramics

2010 ◽  
Vol 146-147 ◽  
pp. 1013-1016
Author(s):  
Yong Ping Pu ◽  
Yu Qin Mao ◽  
Ji Feng Wei
Keyword(s):  
Room Temperature ◽  
Spinel Phase ◽  
Solid State Reaction Method ◽  
Positive Temperature Coefficient ◽  
Room Temperature Resistivity ◽  
Positive Temperature ◽  
Clear Cut ◽  
Temperature Coefficient Of Resistivity ◽  
Synthetic Routes ◽  
Temperature Resistivity

Zn-Ni-Ti-O system ceramics were prepared by solid state reaction method using two different routes. The positive temperature coefficient of resistivity (PTCR) behavior and microstructure were investigated in terms of different composition and synthetic routes. It was found that using ZnO, NiO and TiO2 as the starting materials (route A), the prepared ceramics exhibited low room temperature resistivity (ρRT was ~102 Ω•cm) and inferior resistivity jump (ρmax/ρmin<50) starting at the temperature when it began to rise. However, using ZnOss (Zn0.95Ni0.05O), NiOss (Ni0.55Zn0.45O) and spinel phase (ZnNiTiO4) as starting materials (route B), the ceramics revealed ρRT >103 Ω•cm and marked resistivity jump (ρmax/ρmin was ~102) starting at ~200 °C. The microstructure showed that the ceramics prepared by route B possessed clear-cut grain boundaries but the grains of ceramics prepared by route A were irregular shape and distribution.

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.

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.

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