STRUCTURAL AND MAGNETIC PROPERTIES OF Y1-xZrxBa2Cu3O7-δ SUPERCONDUCTING COMPOUNDS

2000 ◽  
Vol 14 (07n08) ◽  
pp. 285-290 ◽  
Author(s):  
R. REDAC ◽  
C. SBARCIOG ◽  
I. COSMA ◽  
G. BORODI ◽  
I. POP
Keyword(s):  
Critical Temperature ◽  
Zirconium Oxide ◽  
Room Temperature ◽  
Sintering Temperature ◽  
Linear Increase ◽  
X Ray ◽  
Superconducting Compounds ◽  
Structural And Magnetic Properties ◽  
Points Of View ◽  
Material Series

The high-T c Y 1-x Zr x Ba 2 Cu 3 O 7-δ superconductive ceramic material series with x = 0.01, 0.05 and 0.10 was sintered. The system was investigated from the structural and magnetic points of view. The room temperature X-ray pattern shows only orthorhombic reflection and unreacted zirconium oxide reflection. The temperature dependence of the magnetic susceptibility between liquid nitrogen and room temperature reflects a diamagnetic superconductive transition. The zirconium presence in the superconducting compounds determined the approximate linear increase of the critical temperature. The sintering temperature increase between 1200 and 1260 K lowers monotonously the critical temperature between 112 and 91.5 K.

PHASE STRUCTURE, PIEZOELECTRIC AND MULTIFERRIOC BEHAVIOR OF (K0.48Na0.52)NbO3-Co2O3 PIEZOELECTRIC CERAMICS

2011 ◽  
Vol 04 (03) ◽  
pp. 225-229 ◽  
Author(s):  
WENJUAN WU ◽  
DINGQUAN XIAO ◽  
JIAGANG WU ◽  
JING LI ◽  
JIANGUO ZHU
Keyword(s):  
Room Temperature ◽  
Sintering Temperature ◽  
Magnetic Behavior ◽  
Orthorhombic Phase ◽  
Piezoelectric Ceramics ◽  
X Ray Diffraction ◽  
Two Phase ◽  
X Ray ◽  
Solid State Sintering ◽  
Sintering Method

( K 0.48 Na 0.52) NbO 3-x% Co 2 O 3 (x = 0, 0.03 and 0.05) (KNN-x% Co2O3 ) lead-free piezoelectric ceramics were prepared by the conventional solid-state sintering method. An orthorhombic phase was observed for all KNN-x% Co2O3 ceramics at room temperature, and two phase transitions were confirmed by the high temperature X-ray diffraction and the temperature dependence of the dielectric constant. The Co2O3 greatly improves the density and decreases the sintering temperature of KNN ceramics. The KNN-0.05 mol%Co2O3 ceramic exhibits good properties (d33 = 120 pC/N , k p = 0.41, Q m = 213 and T c = 407°C) and a good age stability. The multiferroic behavior was also observed at room temperature for the KNN-0.05 mol%Co2O3 ceramic, as confirmed by P–E loops and magnetic behavior.

XPS STUDIES OF THE STABILITY OF A ZIRCONIUM CARBIDE FILM IN THE PRESENCE OF ZIRCONIUM OXIDE AND HYDROGEN

1995 ◽  
Vol 02 (03) ◽  
pp. 297-303 ◽  
Author(s):  
P.C. WONG ◽  
Y.S. LI ◽  
K.A.R. MITCHELL
Keyword(s):  
Oxide Film ◽  
Photoelectron Spectroscopy ◽  
Zirconium Oxide ◽  
Room Temperature ◽  
Hydrogen Plasma ◽  
Zirconium Carbide ◽  
X Ray ◽  
The Stability ◽  
Zirconium Oxide Film ◽  
Carbide Component

X-ray photoelectron spectroscopy (XPS) has been used to study the interfacial chemistries of a 65-Å film prepared by depositing zirconium in an oxidizing environment onto a methane-pretreated 11-Å thick zirconium oxide film, which initially was deposited onto a gold substrate. The second metal deposition results in an outermost region composed of a mixed zirconium oxide, while below there is metallic zirconium followed by zirconium carbide and carbon on top of the first zirconium oxide film, which is itself in contact with the gold. The carbide component showed no changes on heating to 425°C, on treating with a hydrogen plasma at room temperature, or on heating the resulting film to 425°C. The oxide layers do show characteristic changes, and this also contrasts with earlier observations for a zirconium sulphide film. The zirconium carbide Zr3d 5/2 component has a binding energy of 180.6 eV.

Effect of Sintering Temperature in Physical-Mechanical Behaviour and in Titanium-Hydroxyapatite Composite Sinterability

2006 ◽  
Vol 530-531 ◽  
pp. 249-254 ◽  
Author(s):  
W.R. Weinand ◽  
F.F.R. Gonçalves ◽  
W.M. Lima
Keyword(s):  
Room Temperature ◽  
Milling Time ◽  
Sintering Temperature ◽  
Microstructural Characterization ◽  
Thermal Treatments ◽  
X Ray ◽  
Hydroxyapatite Composite ◽  
Atmosphere Control ◽  
Ti Powder ◽  
Electronic Microscope

Mechanical alloying (MA) has been successfully used to produce alloys and composites with a high homogeneity degree. In current research, titanium (Ti) powder was mixed with 40, 50% volume of hydroxyapatite (HAp). MA was performed without atmosphere control, at room temperature, for 4.5 hours of milling time, at rotation speed of 300 rpm. Samples of material were compacted in cylindrical form at 350 MPa and sintered in 2.0 flux air (l/min) at 1000, 1100 and 1200oC during 1 hr. The material’s morphological and microstructural characterization, in powder form and in sintered material, was performed by scanning electronic microscope and X-ray diffractometry. Thermal treatments revealed that sintering temperature affects the microstructure, microhardness and the composition of the composites evaluated by EDS.

Room Temperature Ferromagnetism in Powder Form of Sn1-xCrxO2 (x = 0.01, 0.02, 0.03, 0.04 and 0.05) Solid Solution

2009 ◽  
Vol 1201 ◽  
Author(s):  
Kun Xu ◽  
Mitsuru Izumi ◽  
Osami Yanagisawa ◽  
Tetsuya Ida
Keyword(s):  
Room Temperature ◽  
Room Temperature Ferromagnetism ◽  
Lattice Parameter ◽  
Nominal Composition ◽  
Powder Form ◽  
X Ray Diffraction ◽  
Interstitial Position ◽  
X Ray ◽  
Cr Content ◽  
Structural And Magnetic Properties

AbstractStructural and magnetic properties were investigated in the mixed powders of Sn1-xCrxO2 (x = 0.01, 0.02, 0.03, 0.04 and 0.05) in nominal composition. The lattice parameter observed in (110) x-ray diffraction indicates two step changes with increasing Cr content. The occupation of Cr ion at the interstitial position leads to elongation of the lattice parameter for x = 0.01 to x =0.03. Then, the Cr3+ ions are remarkably substituted into the Sn4+ ion site for x = 0.04 to x = 0.05, which results in shortening of the lattice. The lattice parameters for x = 0.01 and 0.02 are larger than x = 0.03 to 0.05. The room temperature ferromagnetism appeared in the sample with x = 0.01 and reaches maximum at the doping rate of x = 0.02; while the magnetization decreases for x > 0.02 was observed. Present study clearly shows the existence of correlation between appearance of ferromagnetism and the structural change.

Structural and Magnetic Properties of Nickel Oxide Nanopowders

2010 ◽  
Vol 168-169 ◽  
pp. 341-344 ◽  
Author(s):  
Nina Mironova-Ulmane ◽  
A. Kuzmin ◽  
J. Grabis ◽  
I. Sildos ◽  
V.I. Voronin ◽  
...  
Keyword(s):  
Raman Spectroscopy ◽  
Magnetic Properties ◽  
Neutron Diffraction ◽  
Nickel Oxide ◽  
Room Temperature ◽  
Squid Magnetometry ◽  
X Ray ◽  
Micro Raman Spectroscopy ◽  
Antiferromagnetic Ordering ◽  
Structural And Magnetic Properties

Structure and magnetic properties of nickel oxide (NiO) nanopowders have been studied by X-ray/neutron diffraction, SQUID magnetometer, and micro-Raman spectroscopy. Our diffraction data indicate that at room temperature all NiO powders are antiferromagnetically ordered and have a rhombohedral (R-3m) phase. The SQUID magnetometry and Raman spectroscopy measurements support the presence of the antiferromagnetic ordering.

Effect of Sintering Temperature on Structure and Dielectric Properties of BZN Ceramics

2012 ◽  
Vol 512-515 ◽  
pp. 1203-1206
Author(s):  
Yun Hui Xu ◽  
Xiao Hong Zhu ◽  
Qiang Zhang ◽  
Jian Guo Zhu ◽  
Ding Quan Xiao
Keyword(s):  
Dielectric Properties ◽  
Loss Tangent ◽  
Room Temperature ◽  
Sintering Temperature ◽  
Microwave Frequency ◽  
Fabrication Technology ◽  
X Ray Diffraction ◽  
X Ray ◽  
Dielectric Constant And Loss ◽  
Different Temperatures

Bismuth zinc niobate [(Bi1.5Zn0.5)(Nb1.5Zn0.5)O7, abbreviated as BZN] ceramics are receiving increasing attention due to their excellent dielectric properties in the microwave frequency range. This work is aimed at improving the fabrication technology of BZN ceramics. BZN ceramic specimens were prepared using the general electronic ceramic technique including milling, calcining, crushing, pressing, and sintering. Different sintering temperatures in the range of 950-1080°C were used to study how sintering temperature affects the structure and dielectric properties of BZN ceramics. The crystallinity and microstructure of the BZN ceramics, which were measured respectively by X-ray diffraction and scanning electron microscopy, were improved with increasing of the sintering temperature. The frequency dependence of the dielectric constant and loss tangent was measured at room temperature from 1 kHz to 1 MHz. The dielectric properties of the specimen sintered at 1050°C were found to be the best, for which the relative permittivity (εr) and the loss tangent (tanδ) are around 146 and 0.005, respectively. It was also foεund that when the sintering temperature was higher than 1000°C, the εrand the tanδ of BZN ceramics sintered at different temperatures were similar. As a result, 1000°C may be an appropriate sintering temperature for BZN ceramics.

Effects of 0.03MF2 – 0.12LiF (M = Ca, Sr, Ba) on the Sintering and Dielectric Properties of SrTiO3 Ceramics

2013 ◽  
Vol 9 ◽  
pp. 1-12
Author(s):  
Laldja Taïbi-Benziada ◽  
Hassiba Kermoun ◽  
Yasmina Belaroussi
Keyword(s):  
Room Temperature ◽  
Single Phase ◽  
Sintering Temperature ◽  
Cubic Phase ◽  
Frequency Range ◽  
X Ray Diffraction ◽  
X Ray ◽  
Frequency Independent ◽  
Cold Pressed ◽  
Piezoelectric Devices

Cold-pressed pellets were prepared from the mixtures SrTiO3- 0.03MF2- 0.12LiF, M = Ca, Sr or Ba, then air-fired at 950 °C for 2 hours. The obtained samples were investigated by X-ray diffraction and scanning electron microscopy. Each ceramic is a perovskite single phase and the relative density reaches 95% for all ceramics. The addition of 3 mol. % of the eutectic composition 1MF2- 4LiF (Tm~ 760 °C) to SrTiO3lowers the sintering temperature of pure strontium titanate from 1400 °C to 950 °C and induces a strong modification in the SrTiO3cubic phase: superlattice reflections are detected and the unit cell symmetry becomes orthorhombic. Dielectric measurements were performed between - 150 °C and 200 °C in the frequency range 20 Hz - 109Hz. The dielectric permittivity εrshowed no maximum in the temperature range investigated and is almost frequency independent. At room temperature, the dielectric losses tanδ are less than 0.1 %. Moreover, the frequency dependence of the complex permittivity exhibits a resonance in the microwave region. These fluorinated ceramics could be of interest in piezoelectric devices and are promising dielectrics for class I capacitors manufactured at low temperature.

scholarly journals Oxygen Sensors for Industrial Application

2021 ◽  
Vol 7 (4) ◽  
pp. 139-152
Author(s):  
José Nhanga
Keyword(s):  
Zirconium Oxide ◽  
Sintering Temperature ◽  
Microstructural Characterization ◽  
Oxygen Sensors ◽  
Molten Metals ◽  
X Ray Diffraction ◽  
X Ray ◽  
Ceramic Electrolytes ◽  
Thermal Sintering ◽  
Two Parameters

The present work aimed to study a family of solid ceramic electrolytes based on magnesium oxide doped zirconium oxide, usually identified as Mg-PSZ (zirconia partially stabilized with magnesia), used in the manufacture of oxygen sensors for molten metals. A set of electrolytes was prepared by mechanical (milling) and thermal (sintering) processing, varying the composition in magnesia and the cooling rate from the sintering temperature. These two parameters are essential in terms of phase composition and microstructure of Mg-PSZ, determining the behavior of these materials. The structural and microstructural characterization was done by means of X-ray diffraction (XRD). The electrical properties were analyzed by impedance spectroscopy in air. In general, the results obtained from various concentrations of dopant, different cooling rates and the same sintering step condition showed an increased conductivity for samples with predominance of high temperature stable phases (tetragonal and cubic).

The Effect of Milling Time and Sintering Temperature on Synthesis of PbTiO3 by Mechanical Alloying

2015 ◽  
Vol 1123 ◽  
pp. 109-113
Author(s):  
Rindang Fajarin ◽  
Hariyati Purwaningsih ◽  
Febri Nugroho
Keyword(s):  
Mechanical Alloying ◽  
Room Temperature ◽  
Milling Time ◽  
Sintering Temperature ◽  
Milling Process ◽  
X Ray Diffraction ◽  
Test Device ◽  
Test Analysis ◽  
X Ray ◽  
Multilayer Actuator

PbTiO3is one of electroceramic materials which can be applied for electronics and microelectronics due to their dielectric, pyroelectric, and piezoelectric properties. The members of PbTiO3-based ferroelectrics are widely used in multilayer, actuator and sensor capacitor. At room temperature, PbTiO3has a tetragonal perovskite structure. In this research, PbTiO3particles are synthesized by mechanical alloying method with variation of milling time and sintering temperature. The milling time variation is taken for 10, 20 and 30 hours. Sintering temperature variation is performed at 850, 900 and 1000°C. The powders used in the milling process are PbO and TiO2powders. X-Ray Diffraction (XRD) and Scanning Electron Microscopy–Electron Difraction X-ray (SEM-EDX) are performed to analyze the formation of PbTiO3phase. It is found that the synthesized powders contain 100% PbTiO3phase for all sintering temperatures. The PbTiO3particles have agglomeration shape with a broad particle size. The electrical properties of PbTiO3are measured using electrical test device. Electricity test analysis shows that the synthesized PbTiO3behaves as semiconductor-like.

SYNTHESIS, STRUCTURAL AND MAGNETIC PROPERTIES OF DOUBLE PEROVSKITES Sr2CrWO6

2005 ◽  
Vol 19 (01n03) ◽  
pp. 537-540 ◽  
Author(s):  
T. S. CHAN ◽  
R. S. LIU ◽  
C. Y. HUANG
Keyword(s):  
Crystal Structure ◽  
Valence State ◽  
Room Temperature ◽  
Standard Sample ◽  
Double Perovskite ◽  
Lattice Parameter ◽  
Double Perovskites ◽  
X Ray ◽  
Structural And Magnetic Properties ◽  
X Ray Absorption

The double perovskite ( Sr 2 CrWO 6) has been prepared in polycrystalline state by solid state reaction. At room temperature, the crystal structure is cubic (space group: Fm3m) with lattice parameter of 7.8200(2) (Å). Both ρ( H =0) and ρ( H =5 T ) show a semiconductor-like behavior over the whole temperature range up to 5 K. The highest MR(magnetoresistance) value of 55% ( H =5 T ) was observed at 25 K. The valence state of Cr was determined by the X-ray absorption spectroscopy at Cr -L edge. The results, compared to the standard sample, show that the valence state of Cr is 3+.

Sign in / Sign up

Export Citation Format

Share Document