Determining superconducting parameters from analysis of magnetization fluctuation for CaLaBaCu3O7−δ superconductor

In this work, we report analysis of magnetization fluctuations for the CaLaBaCu3O7−δ superconducting system. We describe a procedure for extracting the penetration depth λ(T) and the coherence length ξ parameters from the magnetization, as a function of the applied magnetic field. This procedure takes the vortex fluctuation into account. The data of the magnetization excess ΔM(T) are analyzed for different values of temperature in the interval from 65 to 73 K. For several magnetic fields we observed a crossover in the magnetization curves at the characteristic temperature value T*=72.2 K. We calculated the data of magnetization excess from the curves of magnetization as a function of the logarithm of the applied field. This procedure was performed for polycrystalline samples of CaLaBaCu3O7−δ by using the proposition of Bulaevskii, Ledvij and Kogan. We notice that the values for these superconducting parameters are in agreement with reports for high-temperature superconductors.