Thermische Tieftemperatureigenschaften von Seltenerd-Übergangsmetall-Borkarbiden

The present work reports on thermal low-temperature properties of rare earth transition metal borocarbides such as specific heat, thermal conductivity and thermopower. The influence of structural disorder, caused by stoichiometric variations and substitutions of the rare earth element or the transition metal, on the thermal and superconducting low-temperature properties is investigated. The structural disorder results in the reduction of the superconducting transition temperature Tc, of the Sommerfeld value gamma, of the upper critical magnetic field Hc2(0), of the negative curvature of the H-dependence of the T-linear specific heat contribution gamma(H), and in the reduction of the positive curvature of Hc2(T) near Tc. But isoelectronic rare earth substitutions do not result in the transition from clean to dirty limit. Due to Pt-substitutions similar reductions of thermal and superconducting properties are observed. The behaviour of Hc2(0) and the concentration dependence of the positive curvature of Hc2(T) near Tc point to the transition from clean to quasi-dirty limit in the case of Pt-substitutions.

Level thesis:degree_level

thesis.doctoral

Grantor dc:publisher

Technische Universität Dresden

Year

2002

Author dc:creator

• Lipp, Dieter

Contributors dc:contributor

• Gladun, Alexander
• Winzer, Klaus
• Wosnitza, Jochen

• Borkarbide
• Elektrischer Widerstand
• Seltenerd
• Spezifische Wärmekapazität
• Strukturelle Unordnung
• Supraleiter
• Supraleitung
• Thermokraft
• Tiefe Temperaturen
• Wärmeleitung
• Übergangsmetall
• Borocarbides
• Electrical Resistivity
• Low Temperatures
• Rare Earth
• Specific Heat
• Structural Disorder
• Superconductivity
• Superconductor
• Thermal Conductivity
• Thermopower
• Transition Metal