Abstract
The temperature dependence of the complex magnetic susceptibility χ′+χ″ of various YBCO films is investigated at different amplitudes of the exciting field Hac. It is found that when the temperature Tm at which the maximum is observed on the χ″(T) curve is plotted as a function of Hacα (the parameter α=1, 1/2, or 2/3, depending on the character of the coupling between crystallites), a kink appears at a certain field Hac=H1*. It is suggested that the temperature Tc1 obtained by extrapolating the Tm(Hac2/3) curve from the high-field region to zero field is the Berezinskii–Kosterlitz–Thouless transition temperature TBKT. This suggestion is based on a comparison of the present results with published data from a study of the complex susceptibility of a GdBa2Cu3O6.75 single crystal for directions of Hac parallel to the c axis of the single crystal and in its ab plane, and also on the coincidence of the calculated values of certain characteristic temperatures near the BKT transition with our experimental values.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
