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Rare earth elements with large ionic radius were substituted for yttrium in Y123 superconducting melt textured bulk samples. The solidification rate in (Nd,Sm)123 was found to significantly increase in a wider solidification range and higher recrystallization rate than Y123. Comparisons were also conducted among directionally solidified (Y,Sm,Nd)1Ba2Cu3O7-x bulk bars developed using the horizontal Bridgman method.

The use of microsecond pulsed deposition to achieve anodic oxidation of YBa2Cu3O(7-x) thin films at room temperature is investigated. Specifically, currents of up to 15.2 A were applied to oxygen-deficient thin films in aqeous solution at five kilohertz for a period of 1.3 microsecond. The procedure, which enhanced the oxygen stoichiometry of the films, restored the superconducting capabilities and modified the microstructure of the films.

We present measurements of the microwave resistivity at 48 GHz in YBa[sub 2]Cu[sub 3] O[sub 7]-δ film, as a function of the temperature and the magnetic field. The magneto-dissipation from 60 K up to a few kelvins below T[sub c] finds a quantitative description in terms of free flux flow. Approaching T[sub c], the data are not consistent with a dissipative mechanism based solely on flux dynamic. Fluxon viscosity is measured as a function of the temperature, and the in-plane coherence length is estimated. The analysis of the zero-field transition at 48 GHz in terms of anisotropic renormalized fluctuations yields identical estimate. [ABSTRACT FROM AUTHOR]

Describes a cryostatic setup to perform photothermal deflection measurements from room temperature. Use of gaseous nitrogen as a medium where the photodeflection is produced; Sample application to high-temperature superconductors and yttrium-iron garnets.

Interferometric thermal diffusivity measurements and elastic constants obtained by ultrasonic techniques on YFeAlO (with ϰ 4 0, 0.4, 0.8, 1.1) ceramic samples are presented and discussed. The phonon mean free path is given as a function of ϰ using the Boltzmann transport equation. [ABSTRACT FROM AUTHOR]

Samarium element has been substituted to yttrium in Y123 superconducting melt textured bulk samples in order to make the whole fabrication process much faster. A preliminary comparison between directionally solidified YBaCuO and SmBaCuO bulk bars fabricated with the horizontal Bridgman method has been done. The different microstructural and superconducting features are studied by means of X-ray, SEM analysis, ac and dc susceptibility measurements. The quality of Sm123 samples appears comparable with the Y123 one grown using an almost two orders of magnitude lower pulling rate. [ABSTRACT FROM AUTHOR]

Superconducting films of YBaCuO were deposited in situ on LaAlO substrates using single-target 90° off-axis sputtering. The obtained films have tipical T values of 91K. Surface resistance measurements on as-grown films reach 1.1 mΩ at 77K and 10GHz; whilst on ion-etched patterned resonant lines R (77K, 10GHz) it is about 10mΩ. [ABSTRACT FROM AUTHOR]

Rare Earth (Nd,Sm) elements, having relatively large ionic radius, have been substituted for Yttrium in Y123 superconducting melt textured bulk samples. In (Nd,Sm)123 a wider solidification range and higher recrystallization rate than Y123 significantly increase the solidification rate, making the whole process much faster. A preliminary comparison among directionally solidified (Y,Sm,Nd)/sub 1/Ba/sub 2/Cu/sub 3/O/sub 7-x/ bulk bars fabricated by the Horizontal Bridgman method has been done. The different microstructural and superconducting features are studied by X-ray, SEM analysis, and ac and dc magnetic measurements. The (Nd,Sm)123 samples, appear comparable to Y123 grown with a pulling rate almost two orders of magnitude lower. [ABSTRACT FROM PUBLISHER]