Magnetization as a function of field parallel to the c axis shows an anomalous secondary peak for a single-crystal Tl2Ba2CuO6. The peak disappears above a crossover temperature Tcr, which is correlated with a crossover in the irreversibility line Hrev(T). For TTcr, Hrev(T)(1-T/Tc)n with n=3/2; for T<Tcr, Hrev(T) increases with 1/T exponentially, an indication of melting of two-dimensional (2D) vortices. Combined with magnetic-relaxation measurements at T<Tcr, we suggest the anomalous magnetization in this system is due to dimensional crossover from 3D to 2D vortex structure.
ASJC Scopus subject areas
- Condensed Matter Physics