Experimental study of partial substitution of copper with 3d elements in 123 superconductors
About forty superconducting samples of Y and Sm, doped with different concentrations of Mn, Fe, Co, Ni and Zn, were prepared. These samples were characterized by x-ray diffractometry, microprobe analysis, resistance measurements, and SQUID susceptometry. Emphasis was given to the magnetic aspects of the specimens. Two standard procedures were followed with each sample. Mainly, the zero field cooling procedure (ZFC) and the field cooling procedure (FC). In both cases, the magnetic moment was measured at different temperatures after the sample was thermalized. Paramagnetic behavior above T, was observed in all the cases. The experimental results were fitted to the Curie-Weiss law, by using SAS (Statistical Analysis System) programs. From this analysis, a range for the effective magnetic moments of the dopant ions was calculated. Also, the density of states at the Fermi level per Cu ion and the Sommerfeld constants were found for each case. In general, lower transition temperatures and higher density of states D({var epsilon}{sub b}F) for Sm doped specimens were observed. The variation of the density of states or {gamma} with the doping has also been analyzed as a function of N. The author notices {gamma} to be linear in N about N{sub max}. Samarium doped samples showed a larger {gamma}, but the slope {alpha} = (d{gamma}/dN) was generally not rare earth dependent. {alpha} did not correlate with {beta} = (dt{sub c}/dN). It was found that {beta}(Zn) {approximately} {beta}(Mn). This decrease in y at N{sub max} was not anticipated in the Matthias' rule.
- Research Organization:
- South Carolina Univ., Columbia, SC (United States)
- OSTI ID:
- 5576819
- Resource Relation:
- Other Information: Thesis (Ph.D.)
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
COBALT
METALLURGICAL EFFECTS
COPPER OXIDES
TRANSITION TEMPERATURE
IRON
MANGANESE
NICKEL
SAMARIUM OXIDES
SUPERCONDUCTORS
YTTRIUM OXIDES
ZINC
COPPER IONS
CURIE-WEISS LAW
DOPED MATERIALS
FERMI LEVEL
MAGNETIC MOMENTS
MICROANALYSIS
X-RAY DIFFRACTION
CHALCOGENIDES
CHARGED PARTICLES
COHERENT SCATTERING
COPPER COMPOUNDS
DIFFRACTION
ELEMENTS
ENERGY LEVELS
IONS
MATERIALS
METALS
OXIDES
OXYGEN COMPOUNDS
PHYSICAL PROPERTIES
RARE EARTH COMPOUNDS
SAMARIUM COMPOUNDS
SCATTERING
THERMODYNAMIC PROPERTIES
TRANSITION ELEMENT COMPOUNDS
TRANSITION ELEMENTS
YTTRIUM COMPOUNDS
360207* - Ceramics
Cermets
& Refractories- Superconducting Properties- (1992-)