Physical properties of ferromagnetic-superconducting coexistent system

TL;DR

This paper investigates the nuclear relaxation rate, ultrasonic attenuation, and electromagnetic absorption in a ferromagnetic-superconducting system, revealing the impact of gapless excitations on these properties and explaining experimental observations.

Contribution

It applies a mean field model to analyze the effects of gapless excitations on various physical properties of ferromagnetic-superconducting systems, providing explanations for experimental results.

Findings

The Hebel-Slichter peak exists but is reduced due to gapless fermions.

Temperature dependence of 1/T1 shows effects of magnetic background.

Model explains experimental measurements of ultrasonic and electromagnetic properties.

Abstract

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.