Superconductivity has been observed in originally semiconducting ceramic samples of La2CuO4 following oxidation in an electrochemical cell at room temperature. After processing, the room-temperature resistivity is low...
Superconductivity has been observed in originally semiconducting ceramic samples of La2CuO4 following oxidation in an electrochemical cell at room temperature. After processing, the room-temperature resistivity is lowered by over an order of magnitude and, on cooling below 150 K, acquires a metallic temperature dependence. The superconducting transition occurs near 45 K. Magnetic-susceptibility measurements confirm the bulk nature of the superconductivity. Furthermore, by reversing the polarization of the cell, semiconducting La2CuO4 can again be produced. The homogeneity of the processed samples was verified by x-ray powder diffraction and energy-dispersive x-ray elemental analysis.
7Li nuclear magnetic resonance (NMR) linewidths and spin-lattice relaxation times for poly(propylene-glycol) complexed with a range of concentrations of LiCF3SO3 are reported over the temperature region from 205 to 40...
C. G. Gray; Comment on ‘‘Fisher information as the basis for the Schrödinger wave equation,’’ by B. Roy Frieden [Am. J. Phys. 57, 1004–1008 (1989)], American Jo
C. G. Gray; Comment on ‘‘Fisher information as the basis for the Schrödinger wave equation,’’ by B. Roy Frieden [Am. J. Phys. 57, 1004–1008 (1989)], American Jo
R. A. Moore; Comment on ‘‘A wave‐packet description of the motion of a charged particle in a uniform magnetic field,’’ by W. Zimmermann, Jr. [Am. J. Phys. 57, 5
R. A. Moore; Comment on ‘‘A wave‐packet description of the motion of a charged particle in a uniform magnetic field,’’ by W. Zimmermann, Jr. [Am. J. Phys. 57, 5
This paper presents a study of the electric field induced migration of Ga and Sb ions during anodic oxidation of Al films on GaSb. Rutherford backscattering spectrometry was used to examine the composition and thickne...
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This paper presents a study of the electric field induced migration of Ga and Sb ions during anodic oxidation of Al films on GaSb. Rutherford backscattering spectrometry was used to examine the composition and thickness of the anodic oxides. Oxide thickening was found to occur at the electrolyte oxide and also at the GaSb oxide substrate interface. It was found that Ga and Sb were mobile under the growth conditions and mobile ions resulted in the formation of a surface GaSb oxide. From measurments of the thickness we are able to report on the transport number for the anion and cations in this system. The growth of the surface GaSb oxide is discussed with reference to the intrinsic oxide growth rates in the Al and GaSb.
The accuracy of PIXE analysis is enhanced by having available a complete characterization of the Si(Li) X-ray detector as regards both efficiency and resolution function (lineshape) in the 1–35 keV X-ray energy range...
The accuracy of PIXE analysis is enhanced by having available a complete characterization of the Si(Li) X-ray detector as regards both efficiency and resolution function (lineshape) in the 1–35 keV X-ray energy range. work in both these areas is reviewed, and the dead-layer concept, together with its role in low-energy response, is critically examined. The potential of other spectrometer types including high-purity germanium detectors and diffraction spectrometers is briefly considered.
Bi 2 Sr 2 CaCu 2 O 8+δ can be reversibly intercalated at room temperature with copper and silver using an electrochemical cell. Silver can be intercalated to about 0.01 mole fraction, and enhances the T c by about 15...
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Bi 2 Sr 2 CaCu 2 O 8+δ can be reversibly intercalated at room temperature with copper and silver using an electrochemical cell. Silver can be intercalated to about 0.01 mole fraction, and enhances the T c by about 15 K. Copper intercalates to about 0.4 mole fraction and thereby not only quenches superconductivity completely but, along with increasing the room temperature resistivity considerably, changes the ϱ(T) dependence to make the material appear semiconducting. Deintercalations restores superconductivity. These dramatic and reversible effects suggest that intercalation may be a valuable technique for studying some of the high T c copper oxides.
The accuracy attainable in micro-PIXE analysis is assessed in terms of the X-ray production model and its assumptions, physical realities of the specimen, the necessary data base, and techniques of standardization. NT...
The accuracy attainable in micro-PIXE analysis is assessed in terms of the X-ray production model and its assumptions, physical realities of the specimen, the necessary data base, and techniques of standardization. NTIS reference materials are analyzed to provide the experimental tests of accuracy.
Single crystal open-circuit potential measurements of Ag x TaS 2 /Ag electrochemical cells at 310 K have provided new insight into the Ag x TaS 2 intercalation system by providing evidence of new phases in the stage 1...
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Single crystal open-circuit potential measurements of Ag x TaS 2 /Ag electrochemical cells at 310 K have provided new insight into the Ag x TaS 2 intercalation system by providing evidence of new phases in the stage 1 region, and by clearly showing that the intercalation reaction starts with a two phase region. Potentiometric silver diffusivity measurements using Ag 2 3 TaS 2 single crystals indicate that during intercalation or deintercalation the chemical diffusion coefficient, D̄ , at 310 K is 2±1×10 −8 cm 2 s −1 . Although this is two orders of magnitude smaller than published results using powdered compacts, it still corresponds very much to that of a superionic conductor.
The lattice vibrations and internal modes of polycrystalline CH 2 ClI and CD 2 ClI have been studied as a function of temperature using Raman and far-infrared spectroscopy. Both isotopic forms have four phases; one is...
The lattice vibrations and internal modes of polycrystalline CH 2 ClI and CD 2 ClI have been studied as a function of temperature using Raman and far-infrared spectroscopy. Both isotopic forms have four phases; one is plastic, one is partially ordered and the other two are fully ordered. Some aspects of the structures are discussed.
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