MEASUREMENTS OF CRITICAL CURRENTS AS A FUNCTION OF TEMPERATURE IN YBA2CU3O7-X THIN-FILMS - A COMPARATIVE-STUDY

The critical current density (J(c)) for zero magnetic field has been m easured as a function of temperature in c-oriented thin layers of YBa2 Cu3O7-x prepared by different synthesis methods. One direct and two in direct J(c)(T) methods were employed for each film: transport measurem ents on patterned film constrictions, DC remanent magnetization studie s using the Bean model and non-linear AC screening analysis. Results f rom the indirect methods were calibrated against transport data. Possi ble origins of observed dependences are suggested and calibration proc edures are discussed. The investigation demonstrated the feasibility o f using AC screening analysis in rapid determinations of J(c)(T) close to T(c).