Electrochemical Synthesis and Characterization of NaCuO2

1994 ◽  
Vol 346 ◽  
Author(s):  
Gerald L. Roberts ◽  
Susan M. Kauzlarich
Keyword(s):  
Potassium Hydroxide ◽  
Reference Electrode ◽  
Room Temperature Resistivity ◽  
Cyclic Voltammogram ◽  
X Ray Diffraction ◽  
X Ray ◽  
Hydroxide Melt ◽  
Black Plate ◽  
Temperature Resistivity

ABSTRACTNaCuO2 has been prepared via electrodeposition from a sodium hydroxide/potassium hydroxide melt and characterized by single crystal and powder X-ray diffraction, magnetic susceptibility, and resistivity. Clusters of blue-black plate-like and needle crystals are grown at positive potentials on a platinum anode with a platinum or a zirconium crucible serving as the cathode and a platinum reference electrode. Details of the electrochemical procedure are described, along with a cyclic voltammogram. NaCuO2 exhibits temperature independent paramagnetism over the temperature range 30 – 300 K. Its room temperature resistivity is greater than 106 Ω-cm.

Deposition and characterization of crystalline conductive RuO2 thin films

1995 ◽  
Vol 10 (10) ◽  
pp. 2401-2403 ◽  
Author(s):  
Q.X. Jia ◽  
S.G. Song ◽  
S.R. Foltyn ◽  
X.D. Wu
Keyword(s):  
Thin Films ◽  
Room Temperature Resistivity ◽  
X Ray Diffraction ◽  
Cross Sectional ◽  
Residual Resistance ◽  
X Ray ◽  
Transmission Electron ◽  
Residual Resistance Ratio ◽  
Temperature Resistivity

Highly conductive metal-oxide RuO2 thin films have been successfully grown on yttria-stabilized zirconia (YSZ) substrates by pulsed laser deposition. Epitaxial growth of RuO2 thin films on YSZ and the atomically sharp interface between the RuO2 and the YSZ substrate are clearly evident from cross-sectional transmission electron microscopy. A diagonal-type epitaxy of RuO2 on YSZ is confirmed from x-ray diffraction measurements. The crystalline RuO2 thin films, deposited at temperatures in the range of 500 °C to 700 °C, have a room-temperature resistivity of 35 ± 2 μω-cm, and the residual resistance ratio (R300 k/R4.2 k) is around 5 for the crystalline RuO2 thin films.

Single Crystal Growth and Thermoelectric Properties of Ce5Cu19P12

1998 ◽  
Vol 545 ◽  
Author(s):  
K. J. Proctor ◽  
F. J. DiSalvo
Keyword(s):  
Electrical Resistivity ◽  
Crystal Growth ◽  
Single Crystal ◽  
Single Crystals ◽  
Room Temperature ◽  
Single Crystal Growth ◽  
Room Temperature Resistivity ◽  
X Ray Diffraction ◽  
X Ray ◽  
Temperature Resistivity

AbstractSingle crystals of the known ternary cerium intermetallic Ce5Cu19P12were grown by Sn flux and I2transport methods. The long axis of the black hexagonal needles was confirmed to be the c-axis by single crystal X-ray diffraction. Electrical resistivity of both single crystals and a pressed pellet was measured from 4 - 300 K; the room temperature resistivity is about 400 μΩ-cm for the needle axis of the crystals and about 5 mΩ-cm for the pressed pellet. The thermopower of the pressed pellet was found to be 34 μV/K at room temperature.

Effect of processing parameters on the characteristics of high-Tc superconductor YBa2Cu3Oy

1988 ◽  
Vol 3 (6) ◽  
pp. 1304-1310 ◽  
Author(s):  
Narottam P. Bansal
Keyword(s):  
Room Temperature ◽  
High Temperature Superconductor ◽  
Sintering Temperature ◽  
Processing Parameters ◽  
Room Temperature Resistivity ◽  
Transition Width ◽  
X Ray Diffraction ◽  
High Tc ◽  
X Ray ◽  
Temperature Resistivity

The influence of sintering temperature, sintering and annealing atmospheres, and quench rate on the properties of the high-temperature superconductor YBa2Cu3Oy has been investigated by electrical resistivity and magnetic susceptibility measurements, thermogravimetric analysis, powder x-ray diffraction, and scanning electron microscopy. Room-temperature resistivity and the transition width decreased, and the fraction of the superconducting material and the bulk density increased with increase in the sintering temperature, but had no effect on the transition temperature (Tc) for samples fired in flowing oxygen. A sample that was rapidly quenched from 930 °C to room temperature after sintering in air had a perovskite structure and Tc (onset) ∼90 K but its resistance did not become zero even at 77 K. A sample sintered in air at 930 °C and furnace cooled had Tc (midpoint) of ∼89.6 K and transition width (10%–90%) of ∼2.6 K. The loss and gain of oxygen occurs reversibly in YBa2Cu3Oy.

CHANGES IN PHYSICAL PROPERTIES OF THE HIGH-Tc SUPERCONDUCTOR Y-Ba-Cu-O DUE TO Cu DEFICIENCY

1989 ◽  
Vol 03 (06) ◽  
pp. 499-503 ◽  
Author(s):  
Y.D. YAO ◽  
Y.H. KAO ◽  
J.J. SIMMINS ◽  
R.L. SNYDER ◽  
Z. TAO ◽  
...  
Keyword(s):  
Oxygen Content ◽  
Room Temperature ◽  
Single Phase ◽  
Nonlinear Dependence ◽  
Room Temperature Resistivity ◽  
X Ray Diffraction ◽  
High Tc ◽  
X Ray ◽  
Cu Deficiency ◽  
Temperature Resistivity

Stoichiometry of the well-known high-T c compound YBa 2 Cu 3 O y is modified by varying the Cu concentration in the system, and changes in the oxygen content and superconducting properties are investigated. The oxygen content shows a nonlinear dependence on the Cu concentration. For Cu deficiency up to 20%, the transition temperature T c remains at a nearly constant value of 93 K. X-ray diffraction measurements show that the compound is orthorhombic in this range of stoichiometric variation, and the Cu -deficient superconductor is single phase. The room temperature resistivity increases exponentially while the critical current density decreases exponentially with increasing Cu deficiency. These results indicate that the predominant mechanism for high-T c superconductivity is closely related to the local structure around the Cu and O atoms.

scholarly journals Synthesis and characterization of PbS nanowires doped with Tb3+ ions by using chemical bath deposition method

2019 ◽  
Vol 10 (1) ◽  
pp. 1-7 ◽  
Author(s):  
L. F. Koao ◽  
Fekadu Gashaw Hone ◽  
F. B. Dejene
Keyword(s):  
Band Gap ◽  
Chemical Bath Deposition ◽  
Potassium Hydroxide ◽  
Luminescent Properties ◽  
Deposition Process ◽  
Chemical Bath Deposition Method ◽  
Deposition Method ◽  
X Ray Diffraction ◽  
X Ray

AbstractCrystalline lead sulfide (PbS) nanowires doped with terbium (Tb3+) ions were synthesized by the chemical bath deposition method at room temperature. The powder was obtained from an aqueous solutions using lead acetate dehydrate, terbium nitrate, thiourea, potassium hydroxide and ammonia. The terbium molar concentrations were varied in the deposition process to investigate the effect on the structural, optical, morphological and luminescent properties of PbS nanowires. The crystalline size was found to be dependent on the concentration of the Tb3+ ions used. The estimated average crystalline sizes were calculated from the X-ray diffraction and found to be 34, 33 and 37 nm for PbS: 0% Tb3+, PbS: 0.2% Tb3+ and PbS: 0.5% Tb3+, respectively. The scanning electron microscopy micrographs depict nanowire shape for the undoped as well as Tb-doped samples. The energy-dispersive X-ray and Auger electron spectroscopy analyses confirmed the presence of all the expected elements. The solid powder nanowires exhibited high absorptions in the UV–Vis regions. The band gap energies were estimated in the range of 1.99–2.46 eV. The absorption edge and the band gap energies of these PbS nanowires have shifted depending on the concentration of the dopant. The maximum luminescence intensity was obtained for PbS: 0.2% Tb3+ ions and luminescent quenching was observed for higher terbium concentrations. Graphic abstract

Study on the Effects of (Bi1/2Na1/2)TiO3 Content on the Curie Temperature of (Bi1/2Na1/2)TiO3-BaTiO3 PTCR Ceramics

2011 ◽  
Vol 687 ◽  
pp. 411-415
Author(s):  
Long Xing Yang ◽  
Xing Wen Zhu ◽  
Li Zhe Li ◽  
Wen Zhong Jiang ◽  
Xiao Zhou
Keyword(s):  
Curie Temperature ◽  
Room Temperature ◽  
Ceramic Materials ◽  
Positive Temperature Coefficient ◽  
Lead Free ◽  
Room Temperature Resistivity ◽  
Positive Temperature ◽  
X Ray Diffraction ◽  
X Ray ◽  
Temperature Resistivity

Perovskite-structured (Bi1/2Na1/2)TiO3 (BNT) ferroelectric with Curie temperature about 320°C is considered to be a good candidate of high temperature lead-free materials with a positive temperature coefficient of resistance (PTCR). In this study, lead-free PTCR ceramics with compositions of (1-x)BaTiO3-x(Bi1/2Na1/2)TiO3 (BT-BNT x=0.5-55mol%) were successfully prepared without any additional donor or acceptor dopants. The effects of BNT content on the Curie temperature Tc and the PTC effect of the ceramic materials were investigated. The X-ray diffraction data indicated that BT phase and BNT phase formed a solid solution during sintering even though the x value was up to 55mol%. The Curie temperature Tc of the samples increased from ~130°C to ~216°C with the increase of the BNT amount (x value) from 0.5mol% to 40mol%. However, it decreased when excess BNT was added (x value increased from 40mol% up to 55mol%), which was resulted from the volatile effects of Bi3+ and Na+ ions during sintering. The sample of 0.6BaTiO3- 0.4(Bi1/2Na1/2)TiO3 with Tc =216°C, room-temperature resistivity 104 Ω·cm and Rmax/Rmin= 102.7 was obtained. There is a relationship between the Curie temperature and the cell volume of the perovskite structured lattice.

A Comparative Study of GaN Epitaxy on Si(001) and SI(111) Substrates

1992 ◽  
Vol 242 ◽  
Author(s):  
T. Lei ◽  
T. D. Moustakas
Keyword(s):  
Room Temperature ◽  
Stacking Faults ◽  
Room Temperature Resistivity ◽  
Defect Level ◽  
X Ray Diffraction ◽  
Optical Studies ◽  
X Ray ◽  
Cubic Gan ◽  
Gan On Si ◽  
Temperature Resistivity

ABSTRACTEpitaxial GaN films were grown on Si(001) and (111) substrates, using a two-step process. The films on Si(001) are single crystalline having the zincblende strucutrue, while those on Si(111) have the wurtzite structure. The crystalline qualities of the films were studied by X-ray diffraction. While the zincblende GaN has a perfect cubic structure, the wurtzitic GaN on Si(111) has a considerable amount of stacking faults along (0002) direction, which gives rise to significant zincblende component with (111) orientation. Room temperature resistivity for both type of GaN films was found to be larger than 100 Ω· cm. The temperature dependence of th resistivity gives a defect level at HOmeV for wurtzitic GaN and 80meV for cubic GaN. Optical studies show that GaN on Si(001) has a gap 3.2eV, and GaN on Si(111) has a gap of 3.4eV at room temperature.

The Use of Advanced Analytical Techniques for Characterization of the Chemical, Physical, and Crystallographic Nature of a Surface

1973 ◽  
Vol 31 ◽  
pp. 132-133 ◽  
Author(s):  
R. E. Herfert
Keyword(s):  
Surface Characterization ◽  
Analytical Techniques ◽  
X Ray Diffraction ◽  
Depth Of Penetration ◽  
X Ray ◽  
The Past ◽  
Transmission Electron ◽  
Scanning Electron

Studies of the nature of a surface, either metallic or nonmetallic, in the past, have been limited to the instrumentation available for these measurements. In the past, optical microscopy, replica transmission electron microscopy, electron or X-ray diffraction and optical or X-ray spectroscopy have provided the means of surface characterization. Actually, some of these techniques are not purely surface; the depth of penetration may be a few thousands of an inch. Within the last five years, instrumentation has been made available which now makes it practical for use to study the outer few 100A of layers and characterize it completely from a chemical, physical, and crystallographic standpoint. The scanning electron microscope (SEM) provides a means of viewing the surface of a material in situ to magnifications as high as 250,000X.

High Resolution Replication of Organoclay Surfaces

1982 ◽  
Vol 40 ◽  
pp. 576-577
Author(s):  
W. W. Barker ◽  
W. E. Rigsby ◽  
V. J. Hurst ◽  
W. J. Humphreys
Keyword(s):  
Clay Mineral ◽  
Organic Molecule ◽  
Organic Molecules ◽  
X Ray Diffraction ◽  
Xrd Pattern ◽  
X Ray ◽  
Naturally Occurring ◽  
Silicate Layers ◽  
Mineral Identification

Experimental clay mineral-organic molecule complexes long have been known and some of them have been extensively studied by X-ray diffraction methods. The organic molecules are adsorbed onto the surfaces of the clay minerals, or intercalated between the silicate layers. Natural organo-clays also are widely recognized but generally have not been well characterized. Widely used techniques for clay mineral identification involve treatment of the sample with H2 O2 or other oxidant to destroy any associated organics. This generally simplifies and intensifies the XRD pattern of the clay residue, but helps little with the characterization of the original organoclay. Adequate techniques for the direct observation of synthetic and naturally occurring organoclays are yet to be developed.

Synthesis and characterization of TiN / Ti / AISI 410 coatings

2018 ◽  
Vol 2 (1) ◽  
pp. 7
Author(s):  
S Chirino ◽  
Jaime Diaz ◽  
N Monteblanco ◽  
E Valderrama
Keyword(s):  
Synthesis And Characterization ◽  
Photoemission Spectroscopy ◽  
X Ray Diffraction ◽  
X Ray ◽  
Columnar Grains ◽  
Tin Thin Films ◽  
Steel Aisi ◽  
Interacting Surfaces ◽  
Stainless Steel Aisi

The synthesis and characterization of Ti and TiN thin films of different thicknesses was carried out on a martensitic stainless steel AISI 410 substrate used for tool manufacturing. The mechanical parameters between the interacting surfaces such as thickness, adhesion and hardness were measured. By means of the scanning electron microscope (SEM) the superficial morphology of the Ti/TiN interface was observed, finding that the growth was of columnar grains and by means of EDAX the existence of titanium was verified.  Using X-ray diffraction (XRD) it was possible to observe the presence of residual stresses (~ -3.1 GPa) due to the different crystalline phases in the coating. Under X-ray photoemission spectroscopy (XPS) it was possible to observe the molecular chemical composition of the coating surface, being Ti-N, Ti-N-O and Ti-O the predominant ones.

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