Magnetization of Gd diffused YBa₂Cu₃O7−xsuperconductor: Experiment and theory

The magnetization of Gd diffused YBa 2 Cu 3 O 7− x is measured by a vibrating sample magnetometer (VSM) at selected temperatures (5, 25, 50, 77 K). The experimental results for the magnetization are analyzed in the critical state framework involving Kim—Anderson field dependence J c ( H ) = J c0 /(1 + | H |/ H 0 ) n of critical current density and equilibrium magnetization M eq . It is found that the inclusion of the equilibrium magnetization becomes more important at higher temperatures. At 77 K, the shape of the isothermal M—H hysteresis curve is governed by the equilibrium magnetization. Some superconducting parameters are determined by fitting the calculated curves to the experimental data.