AC susceptibility of YBa2Cu3O7-d superconducting thin film in a   perpendicular field
  The temperature dependence of ac susceptibility of YBCO thin film was measured as a function of frequency and ac field amplitude in a field perpendicular to the film plane. We show that all measured ac susceptibility curves can be caled into a single curve using the peak temperature (Tp) of its imaginary part as the scaling parameter. The frequency effect on ac susceptibility was also measured. As the frequency increases,(Tp)shifts to higher temperature.This effect can be interpreted in terms of flux creep. The temperature T,and field,Hac, dependence of the activation energy obtained from the Arrhenius plot for the frequency(f)and(Tp),can be described as U(Hac,T)=Uo(1-T/Tc)Hac^(-0.18). 
H. Salamati, P. Kameli