Pinning and lower critical field in Tl2Ba2CaCu2Ox single crystals
Bezryadin A. V. , Kopylov V. N. , Krasnov V. M., Larkin V. A. , Ryazanov V. V., Togonidze T. G. , Shchegolev I. F.
The magnetic characteristics of Tl2Ba2CaCu2Ox superconducting single crystals have been measured by two different methods. The anomalous temperature dependence of the penetration magnetic field is linked with a sharp change in the pinning of magnetic flux at temperatures near 40 K.