Dependence of AC susceptibility of polycrystalline RuSr 2GdCu 2O 8 superconductor on magnetic field amplitudes and frequencies

Abstract

Systematic measurements of the AC magnetic susceptibility of polycrystalline RuSr 2GdCu 2O 8 (Ru-1212) samples are reported for various frequencies and magnetic field amplitudes. The study covered frequency range from 22 Hz to 12.5 kHz and field amplitudes between 0.5 and 25 G. The variation of the real part, χ ′, as well as, the imaginary part, χ ″, of AC susceptibility for Ru-1212 samples has been investigated as a function of temperature for different magnetic field amplitudes and frequencies. A qualitative analysis of AC susceptibility response for Ru-1212 superconductor near the transition temperature, T c, is presented. A single distinct peak in the imaginary part of AC magnetic susceptibility versus temperature is typically observed upon entering the superconducting state. The dependence of peak temperature, T p, of the χ ″ on magnetic field amplitude and frequency has been also investigated. It was found that the peak temperature, T p, is shifted to higher temperatures by increasing frequency and to lower temperatures by increasing magnetic fields.