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 S(ω) was derived from the measured values of Z _(sample) and Z _(air). S(ω) 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 S(ω) data could also be scaled successfully at two different temperature zones: below and above the critical temperature T _C. 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 T _C.
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