JC(B) Determination Method With the Help of the Virgin Magnetization Curve of a Superconducting Cylinder

It is well known that the critical current densityJCof a superconducting material depends on the magnetic flux densityB. For practical applications, it is essential to have accurate information aboutJC(B) , which can be obtained from different experimental techniques (transport current, hysteretic cycle, and ac susceptibility). This paper presents a simple and quickJC(B) experimental determination method for a superconducting cylinder. A firstJC(B) experimental evaluation method consists of measuring the magnetization cycleM(B) and determining the width of this cycle for each value ofB. This is generally done using the Bean model, whereJCis considered constant. A more accurate method is presented in this paper. The cylinder first magnetization curveM1(B) is calculated with the Kim model [JC(B) =JC0/(1 + (|B|/BC0))] and with a linear model and compared with the measured first magnetization curveM1mea(B). In so doing,JC0 andBC0 are determined, and the results obtained using bothJC(B) determination methods are compared and discussed.