Vortex States of Tl₂Ba₂CuO_6+δ Studied via ²⁰⁵Tl NMR at 2 Tesla

抄録

We report a ²⁰⁵Tl NMR study of vortex states in an aligned polycrystalline sample of an overdoped high-T_c superconductor, Tl₂Ba₂CuO_6+δ (T_c∼85 K), at a magnetic field of 2 T along the c axis. We observed an imperfect vortex lattice, so-called Bragg glass, at T=5 K, the coexistence of vortex solid and vortex liquid between 10 and 60 K, and vortex melting between 65 and 85 K. No evidence for local antiferromagnetic ordering at vortex cores was found for our sample.