Effects of La-Doping on Phase Structure and Electrical Properties of Pb(Mg1/3Nb2/3)0.67Ti0.33O3 Ceramic

2012 ◽  
Vol 622-623 ◽  
pp. 767-770
Author(s):  
Yong Liu ◽  
Rui Qing Chu ◽  
Zhi Jun Xu ◽  
Shu Ting Wang ◽  
Qing Bin Chi ◽  
...  
Keyword(s):  
Electrical Properties ◽  
Phase Structure ◽  
Doping Level ◽  
Raw Materials ◽  
Pyrochlore Phase ◽  
X Ray Diffraction ◽  
La Doping ◽  
Low X ◽  
Sintering Method ◽  
La Doped

La-doped Pb(Mg1/3Nb2/3)0.67Ti0.33O3 ceramics were fabricated by a two-stage sintering method from conventional raw materials. The effects of La doping on the phase structure and electrical properties of ceramics were investigated. X-ray diffraction analysis showed that the pyrochlore phase increased with the increase of La-doping level. The effects of La doping on the dielectric, ferroelectric and piezoelectric properties of the ceramics were also investigated. The results showed that La doping seriously weakened the electrical properties of the ceramics. The ceramics possess optimum properties (d33=239pC/N, Pr=10.6μC/cm2, Ec=8.5kV/cm, tanδ=0.029, εr = 2250) when the doping level is low (x = 0.02).

Study on Phase Structure and Electrical Properties of La-Doped (K0.5Na0.5)0.94Li0.06NbO3 Ceramics

2011 ◽  
Vol 328-330 ◽  
pp. 1127-1130 ◽  
Author(s):  
Yong Liu ◽  
Rui Qing Chu ◽  
Zhi Jun Xu ◽  
Qian Chen ◽  
Lin Shao ◽  
...  
Keyword(s):  
Electrical Properties ◽  
Phase Structure ◽  
Room Temperature ◽  
Cubic Phase ◽  
X Ray Diffraction ◽  
Conventional Solid State Reaction ◽  
X Ray ◽  
La Doping ◽  
La Doped ◽  
Lower Loss

Lead-free piezoceramics (K0.5Na0.5)0.94-3xLi0.06LaxNbO3were synthesized by the conventional solid-state reaction process. The effect of La-doping on the phase structure and electrical properties of (K0.5Na0.5)0.94Li0.06NbO3ceramics was investigated. X-ray diffraction analysis showed that the crystal structure of the ceramics changed from coexistence of orthorhombic and tetragonal phases to pseudo-cubic phase with the increase of La-doping level, and the change of phase structure seriously weakened the dielectric, ferroelectric and piezoelectric properties of the ceramics. In addition, it was found that the La-doping improved the density of the ceramics and the ceramics became dense. Meanwhile, the ceramics with La-doping displayed a relative lower loss tangent (tanδ) from room temperature to approximately 350°C.

Synthesis and Magnetic Properties of La-Doped Ni Ferrites

2010 ◽  
Vol 148-149 ◽  
pp. 736-739
Author(s):  
Ju Hua Luo
Keyword(s):  
Single Phase ◽  
Raw Materials ◽  
Nominal Composition ◽  
Vibrating Sample Magnetometry ◽  
X Ray Diffraction ◽  
X Ray ◽  
Magnetic Parameters ◽  
Ft Ir ◽  
Mechanochemical Treatments ◽  
La Doped

Ni ferrites doped with lanthanum with a nominal composition of NiFe2-xLaxO4(x=0.05) were obtained by mechanochemical treatments using NiCO3•2Ni (OH)2•4H2O , La2O3 and Fe2O3 as raw materials. Both series of materials were characterised by scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), vibrating sample magnetometry (VSM). The results indicated that the mixture became amorphous stage after ball-milled for 30 h, and single phase NiFe1.95La0.05O4 could be obtained after calcined at 700 for 2 h. The addition of lanthanum resulted in a reduction of all the magnetic parameters evaluated.

Effect of La doping on the structural and electrical properties of SrBi2Ta2O9

2004 ◽  
Vol 811 ◽  
Author(s):  
Ortega Nora ◽  
S. Bhattacharyya ◽  
P. Bhattacharya ◽  
R.R. Das ◽  
R.S. Katiyar
Keyword(s):  
Electrical Properties ◽  
Structural Evolution ◽  
Phase Segregation ◽  
X Ray Diffraction ◽  
Lanthanum Doping ◽  
X Ray ◽  
La Doping ◽  
Structural And Electrical Properties ◽  
Vibrational Characteristics ◽  
La Substitution

ABSTRACTThe effect of anthanum substitution (0-20%) on phase formation, structural evolution and electrical properties of SrBi2Ta2O9 (SBT) ceramics were investigated. X-ray diffraction studies revealed that phase pure SBT bulk samples can be synthesized with lanthanum doping without any phase segregation. Raman spectroscopy was used to understand the lattice vibrational characteristics of La substituted SBT compound. The ferroelectric soft mode at 27 cm−1 was shifted towards the lower frequencies at room temperature with increase in La concentrations. The octahedral stretching mode (O-Ta-O) did not influenced by La substitution in SBT. The x-ray photoemission spectroscopy measurements showed the decrease of binding energy of Bi 4f core levels (5/2 and 7/2) upon La substitution in SBT. The dielectric constant was increased from 120 to 190 up to 10% La doping and decreased with further increase in La concentration.

Effects of YMnO3 Addition on Phase Structure, Microstructure and Electrical Properties of (Na0.515K0.485)0.94Li0.06(Nb0.8Ta0.2)O3 Lead-Free Ceramics

2014 ◽  
Vol 979 ◽  
pp. 167-170
Author(s):  
Pornsuda Bomlai
Keyword(s):  
Grain Size ◽  
Electrical Properties ◽  
Phase Structure ◽  
Dissipation Factor ◽  
Lead Free ◽  
Low Dielectric ◽  
Lead Free Ceramics ◽  
Dielectric Dissipation Factor ◽  
Sintering Method ◽  
Piezoelectric Devices

The (1-x)[(Na0.515K0.485)0.94Li0.06(Nb0.8Ta0.2)O3]-xYMnO3 (x = 0, 0.005, 0.01, 0.015 and 0.02) lead-free ceramics were synthesized by solid-state reaction sintering method. It was found that the addition of YMnO3 affected on the grain size, phase structure and electrical properties of (Na0.515K0.485)0.94Li0.06(Nb0.8Ta0.2)O3 ceramics. The grain size decreased with increasing YMnO3 content (x ≥ 0.01) and led to poor densification. The ceramic doped with 0.5 mol% YMnO3 showed good electrical properties such as d33 = 195 pC/N, kp = 43.9 %, Tc = 292 °C, TO−T = 35 °C, εr = 820 and rather low dielectric dissipation factor = 2.1%. This indicates that 0.5 mol% YMnO3 -doped (Na0.515K0.485)0.94Li0.06(Nb0.8Ta0.2)O3 piezoceramic is an alternative lead-free piezoelectric material for the development of piezoelectric devices working at high temperature.

scholarly journals Structural and electrical characterization of La3+ substituted PMS-PZT (Zr/Ti:60/40) ceramics

2018 ◽  
Vol 36 (1) ◽  
pp. 1-6 ◽  
Author(s):  
H. Menasra ◽  
Z. Necira ◽  
K. Bounabe ◽  
M. Abba ◽  
A. Meklid ◽  
...  
Keyword(s):  
Phase Structure ◽  
Pyrochlore Phase ◽  
Electrical Characterization ◽  
Rhombohedral Phase ◽  
Dielectric Behavior ◽  
X Ray Diffraction ◽  
Conventional Solid State Reaction ◽  
Maximum Dielectric Constant ◽  
Dielectric Constant Decrease

Abstract Pb(1-x)Lax [(Zr0.6Ti0.4)(1-x)(Mn1/3Sb2/3)x]O3 ceramics with x = 0.02, 0.03, 0.04, and 0.05 were synthesized by using a conventional solid state reaction route. The influence of La, Mn, and Sb contents on phase structure, microstructure, and electric properties were investigated. The results of X-ray diffraction (XRD) show that the phase structure of the ceramics transforms from rhombohedral phase to tetragonal phase. However, the minority pyrochlore phase appears on the micrographs of XRD and SEM if the doping concentration is greater than 2 mol%. The grain size of the ceramics gradually increases (from 1.36 μm to 1.57 μm) with increasing doping. The dielectric properties of the ceramics have been measured as a function of temperature in the range of 20 °C to 430 °C at 1 kHz. The results indicate that the transition temperature and the maximum dielectric constant decrease with increasing PL-PMS content in the system. These results clearly show the significance of PL-PMS in controlling the dielectric behavior of the PL-PMS-PZT system.

Fabrication and Photoelectric Properties of La-Doped ZnO Nanofibers via Electrospinning

2015 ◽  
Vol 733 ◽  
pp. 257-260 ◽  
Author(s):  
Yi Chen Liu ◽  
Xu Yan ◽  
Wen Peng Han ◽  
Hong Di Zhang ◽  
Yun Ze Long
Keyword(s):  
Crystal Structure ◽  
Light Illumination ◽  
X Ray Diffraction ◽  
X Ray ◽  
La Doping ◽  
Photoelectric Properties ◽  
Zno Nanofibers ◽  
Doped Zno ◽  
La Doped ◽  
Scanning Electron

La-doped ZnO nanofibers were fabricated via electrospinning and calcination at 800°C. The surface morphology and crystal structure of the La-doped ZnO nanofibers were characterized by scanning electron microscopy (SEM) and X-ray diffraction (XRD). The photoelectric properties of La-doped ZnO nanofibers were also investigated. It was found that the photoelectric current increased obviously under light illumination (308 nm and 365 nm). However, the photocurrent reduced with increasing La-doping level, which may be ascribed to the increased defects inducing by La-doping.

ENHANCED MULTIFERROIC PROPERTIES OF BiFeO3 CERAMICS BY Mo DOPING

2011 ◽  
Vol 25 (18) ◽  
pp. 1521-1528 ◽  
Author(s):  
X. ZHANG ◽  
G. Q. ZHANG ◽  
J. MIAO ◽  
X. G. XU ◽  
Y. JIANG
Keyword(s):  
Electrical Properties ◽  
Electric Field ◽  
Phase Structure ◽  
Ferroelectric Properties ◽  
Sol Gel ◽  
X Ray Diffraction ◽  
X Ray ◽  
Multiferroic Properties ◽  
Mo Doping ◽  
Polarization Electric Field

We have investigated the magnetic and electrical properties of multiferroic BiFe 1-x Mo x O 3 ceramics ( BFMO , x = 0.0%, 0.2%, 0.5% and 0.8%) prepared by the sol–gel method. The phase structure of BFMO samples were confirmed by X-ray diffraction. It was found that the substitution of Mo is responsible for the increasing of the magnetization in BFMO ceramics. Moreover, both dielectric and polarization-electric field properties suggest that the Mo doping could improve the dielectric and ferroelectric properties in BFMO ceramic.

Phase Structure, Microstructure and Electrical Properties of Lead-Free (1-x) [Na0.515K0.485]0.94Li0.06(Nb0.99Ta0.01)O3 - BiAlO3 Ceramics

2013 ◽  
Vol 747 ◽  
pp. 781-784 ◽  
Author(s):  
Pornsuda Bomlai
Keyword(s):  
Phase Transition ◽  
Electrical Properties ◽  
Phase Structure ◽  
Piezoelectric Properties ◽  
Perovskite Phase ◽  
Lead Free ◽  
Cubic Phase ◽  
X Ray Diffraction ◽  
Polymorphic Phase Transition ◽  
Dielectric And Piezoelectric Properties

Lead-free (1-x)[(Na0.515K0.485)0.94Li0.06(Nb0.99Ta0.01)O3]-xBiAlO3 (NKLNT-BA; x = 0, 0.005, 0.010, 0.015, and 0.020) ceramics were fabricated by a conventional mixed-oxide method. The effects of BiAlO3 addition on the phase structure, microstructure and electrical properties of ceramic were then studied. The result indicated that grain size decreased with increasing of BiAlO3 content. In the composition range studied, the perovskite phase with the coexistence of the orthorhombic and tetragonal phases was identified at approximately x 0.005 by the X-ray diffraction analysis and dielectric spectroscopy, which led to a significant enhancement of the piezoelectric properties. The tetragonality increased with further increasing x. The temperature dependence of dielectric properties showed that the addition of BiAlO3 slightly decreased the ferroelectric tetragonal-paraelectric cubic phase transition temperature (TC), but greatly shifted the polymorphic phase transition from the ferroelectric orthorhombic to the ferroelectric tetragonal phase (TOT) to lower room temperature. The dielectric and piezoelectric properties are enhanced for the composition near the orthorhombic-tetragonal polymorphic phase boundary. The unmodified-(Na0.515K0.485)0.94Li0.06(Nb0.99Ta0.01)O3 ceramics exhibit optimum electrical properties (d33 = 225 pC/N and TC = 418°C).

Synthesis of Industrial Ceramic (Cordierite) from Iraqi Raw Materials Through Solid-State Sintering Method

2020 ◽  
Vol 54 (1A) ◽  
pp. 23-34
Author(s):  
Mojahid Najim
Keyword(s):  
Rice Husk Ash ◽  
Raw Materials ◽  
Western Desert ◽  
Silica Sand ◽  
X Ray Diffraction ◽  
Soaking Time ◽  
X Ray ◽  
Pure Silica ◽  
Dry Pressing ◽  
Sintering Method

This study uses Iraqi raw materials (Western Desert) which include: Urdhuma silica sand, Duekhla kaolinitic claystone, flint clay, porcelanite, and karst bauxite, alongside other materials (pure silica created as by-product of Qaim phosphate manufacturing processes.), amorphous silica (silica from rice husk ash), Mg (OH)2, and MgCO3. The raw materials have been crushed and milled into sizes smaller than 45µ except the silica sand and kaolin that have been miled into different sizes 20 and 45 µ. Twenty-seven mixtures of different proportions were prepared from the above-mentioned materials. Ninety-two disk samples were formed by semi-dry pressing using the pressing force of 1000 kg/cm2. Those test samples were dried and fired at the temperatures of 1100, 1200, and 1300 ̊°C with temperature rises 50 °C/h and the soaking time of 2 h. X-ray diffraction of those samples shows a difference in the mineral structure according to the firing temperature and the chemical composition of the mixtures. The samples containing the mixtures of 70% Kaolin, 5% pure silica (Qaim), and 25% Magnesite that were fried at the temperature of 1300 ̊°C entirely consist of Cordierite.

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