Compensation of magnetic impurity effect in superconductors by radiation damage

Impurity Eeects in Superconductors

Magnetic Hardening of Sm2Fe17N3 by Radiation Damage

Pinning type coercivity has been induced in large sø50 mmd particles of Sm2Fe17N3 by irradiation with 5 GeV Pb561 ions. Mössbauer spectroscopy is used to analyze the structure of the defects and estimate their volume. Magnetization measurements indicate that the induced defects are anisotropic in shape. A model of strong pinning by cylindrical defects is employed to deduce a defect radius of or...

Marginal Fermi liquid resonance induced by a quantum magnetic impurity in d-wave superconductors.

We consider a model of an Anderson impurity embedded in a d(x(2)-y(2))--wave superconducting state to describe the low-energy excitations of cuprate superconductors doped with a small amount of magnetic impurities. Because of the Dirac-like energy dispersion, a sharp localized resonance above the Fermi energy, showing a marginal Fermi liquid behavior ( omega ln omega as omega-->0), is predicted...

Bound State and Order Parameter Mixing Effect by Nonmagnetic Impurity Scattering in Two-band Superconductors

We investigate nonmagnetic impurity effects in two-band superconductors, focusing on the effects of interband scatterings. Within the Born approximation, it is known that interband scatterings mix order parameters in the two bands. In particular, only one averaged energy gap appears in the excitation spectrum in the dirty limit. [G. Gusman: J. Phys. Chem. Solids 28 (1967) 2327.] In this paper, ...

Anomalous impurity effects in nonadiabatic superconductors

– We show that, in contrast with the usual electron-phonon Migdal-Eliashberg theory, the critical temperature Tc of an isotropic s-wave nonadiabatic superconductor is strongly reduced by the presence of diluted non-magnetic impurities. Our results suggest that the recently observed Tc-suppression driven by disorder in K3C60 (Phys. Rev. B 55, 3866 (1997)) and in Nd2−xCexCuO4−δ (Phys. Rev. B 58, ...