The glass transitions of the vortex system in Au-ion irradiated YBa2Cu3Oy films have been studied by the measurements of transport properties as a function of magnetic field B and angle Θ of B to the direction of columnar defects. At χ = 0°, we find an anomalous upturn behavior of the glass transition line Bg(T) at B ∼ BΦ/3, where Bos is the matching field. In B > BΦ/3, the χ dependence of glass transition temperature Tg reveals cusplike behavior with a peak at χ = 0°, which is consistent with the Bose glass theory. In B < BΦ/3, on the other hand, Tg is almost independent of χ, suggesting the system undergoes the vortex glass transition induced by the inherent point-like defects.
ASJC Scopus subject areas
- Atomic and Molecular Physics, and Optics
- Materials Science(all)
- Condensed Matter Physics