7 research outputs found
Microscopic theory of vortex dynamics in homogeneous superconductors
Vortex dynamics in fermionic superfluids is carefully considered from the
microscopic point of view. Finite temperatures, as well as impurities, are
explicitly incorporated. To enable readers understand the physical
implications, macroscopic demonstrations based on thermodynamics and
fluctuations- dissipation theorems are constructed. For the first time a clear
summary and a critical review of previous results are given.Comment: Presentations are made more straightforward. A detailed presentation
that why the vortex friction is finite when the geometric phase exists, as
required by referees, though I think it is obviou
Magnetoresistivity in MgB2 as a probe of disorder in p- and s-bands
In this paper we present normal state magnetoresistivity data of magnesium
diboride epitaxial thin films with different levels of disorder, measured at
42K in magnetic fields up to 45 Tesla. Disorder was introduced in a controlled
way either by means of neutron irradiation or by carbon doping. From a
quantitative analysis of the magnetoresistivity curves with the magnetic field
either parallel or perpendicular to the plane of the film, we extract the ratio
of the scattering times in p- and s-bands. We demonstrate that the undoped
unirradiated thin film has p scattering times smaller than s ones; upon
irradiation, both bands become increasingly more disordered; eventually the
highly irradiated sample (neutron fluence 7.7X1017 cm-2) and the C-doped sample
have comparable scattering times in the two types of bands. This description of
the effect of disorder in the two kinds of bands on transport is consistent
with the residual resistivity values and with the temperature dependence of the
resistivity.Comment: 19 pages, 3 tables, 2 figure