Magnetic scattering and unusual behavior of the critical fields and other parameters: Application to borocarbides

The pair-breaking effect and its impact on the properties of borocarbides i s studied. The pair-breaking effect caused by localized magnetic moments dr astically affects the superconducting properties. Interaction between the m agnetic moments and the resulting ordering trend lead to a behavior entirel y different from the conventional picture. The main focus is on the behavio r of the upper (H-c2) and lower (H-c1) critical fields. In addition, the te mperature dependence of several quantities (penetration depth, coherence le ngth, etc.) has been calculated. The theory has been applied to the borocar bide LuNi2B2C and is in very good agreement with the recent experimental da ta.