Modelling of Ac susceptibility of thin superconducting disk in perpendicular magnetic fields

A theoretical model for the real and imaginary parts of the susceptibility of superconducting thin disk as a function of a perpendicular applied magnetic field were derived in order to do the calculation according to this model mat lab codes were written the calculation was done with the assumption that the critical current density is independent of the applied magnetic field (the bean critical state model) the real and imaginary parts of susceptibility was then calculated at different films thickness and at different critical current densities the calculation was repeated with the assumption that the critical current densities are magnetic field dependent by using the concepts of Kim and exponential models it was found that the magnetic field of full penetration increases H_p = 0.9267d + 1.0984 for the bean model H_p = 17.772d + 132.18 for the exponential model and H_p = 19.363d - 159.88 for the Kim model moreover the magnetic field of full penetration increases linearly as the critical current densities increases the results of using the ac susceptibility model showed agreement with some of published works. (author)