$J_{C}(B)$ Determination Method With the Help of the Virgin Magnetization Curve of a Superconducting Cylinder

Abstract

It is well known that the critical current density JC of a superconducting material depends on the magnetic flux density B . For practical applications, it is essential to have accurate information about JC(B) , which can be obtained from different experimental techniques (transport current, hysteretic cycle, and ac susceptibility). This paper presents a simple and quick JC(B) experimental determination method for a superconducting cylinder. A first JC(B) experimental evaluation method consists of measuring the magnetization cycle M(B) and determining the width of this cycle for each value of B. This is generally done using the Bean model, where JC is considered constant. A more accurate method is presented in this paper. The cylinder first magnetization curve M 1(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 curve M 1mea(B). In so doing, JC0 and BC0 are determined, and the results obtained using both JC(B) determination methods are compared and discussed.