Frequency and temperature dependence of ac loss and scaling study of a high-temperature cuprate superconductor

Abstract

Impedances of a small solenoid were measured at different frequencies and temperatures both without and with a cylindrical sample of high-temperature superconductor (HTSC) material as the core. A parameter was derived from the measured values of and . was analysed and found to be proportional to the ac loss of the sample in the core. The temperature dependence of the ac loss was found to be in good agreement with the two-fluid model for different HTSC materials (ReBCO-type). The data could also be scaled successfully at two different temperature zones: below and above the critical temperature TC. It is also found that the temperature dependence of ac loss is dominated by two different characteristic temperatures in two different zones: below and above TC.

Electric field noise in a high-temperature superconducting surface ion trap

“…The clear correlation between the onset of the noise plateau and the superconducting transition, T * ≈ T c , indicates a relation between the dominant noise and the YBCO trap material. In fact, many physical quantities in high-temperature superconductors show a temperature dependence similar to the dependence of the noise in our trap: the density of superconducting charge carriers [36], AC loss [37], voltage noise caused by resistance fluctuations [38], the magnetic susceptibility [39], or the frequency variation of phonon modes [40]. The fact that there is no marked jump in noise at T = T c , nor a change in frequency scaling, suggests a single noise source to be dominant over the entire temperature range.…”