373 research outputs found
Theory of the tunneling spectroscopy of ferromagnetic superconductors
We study tunneling conductance in normal metal / insulator / ferromagnetic
superconductor junctions. The tunneling spectra show a clear difference between
spin-singlet s-wave pairing, spin-triplet opposite spin pairing and
spin-triplet equal spin pairing: These pairings exhibit, respectively, gap
struture, double peak structure and zero bias peak in the spectra. The obtained
result may serve as a tool for determining the pairing symmetry of
ferromagnetic superconductors.Comment: 4 pages, 2 figure
Pairing symmetry signatures of T1 in superconducting ferromagnets
We study the nuclear relaxation rate 1/T1 as a function of temperature for a
superconducting-ferromagnetic coexistent system using a p-wave triplet model
for the superconducting pairing symmetry. This calculation is contrasted with a
singlet s-wave one done previously, and we see for the s-wave case that there
is a Hebel-Slichter peak, albeit reduced due to the magnetization, and no peak
for the p-wave case. We then compare these results to a nuclear relaxation rate
experiment on UGe2 to determine the possible pairing symmetry signatures in
that material. It is seen that the experimental data is inconclusive to rule
out the possibility of s-wave pairing in .Comment: 4 pages, 4 figure
A quantitative study of spin noise spectroscopy in a classical gas of K atoms
We present a general derivation of the electron spin noise power spectrum in
alkali gases as measured by optical Faraday rotation, which applies to both
classical gases at high temperatures as well as ultracold quantum gases. We
show that the spin-noise power spectrum is determined by an electron spin-spin
correlation function, and we find that measurements of the spin-noise power
spectra for a classical gas of K atoms are in good agreement with the
predicted values. Experimental and theoretical spin noise spectra are directly
and quantitatively compared in both longitudinal and transverse magnetic fields
up to the high magnetic field regime (where Zeeman energies exceed the
intrinsic hyperfine energy splitting of the K ground state)
Physical properties of ferromagnetic-superconducting coexistent system
We studied the nuclear relaxation rate 1/T1 of a
ferromagnetic-superconducting system from the mean field model proposed in
Ref.14. This model predicts the existence of a set of gapless excitations in
the energy spectrum which will affect the properties studied here, such as the
density of states and, hence, 1/T1. The study of the temperature variation of
1/T1(for T<Tc) shows that the usual Hebel-Slichter peak exists, but will be
reduced because of the dominant role of the gapless fermions and the background
magnetic behavior. We have also presented the temperature dependence of
ultrasonic attenuation and the frequency dependence of electromagnetic
absorption within this model. We are successful in explaining certain
experimental results.Comment: 10 Pages, 9 figute
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