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要旨:
We have combined magnetic measurements and imaging of the vortex lattice at low fields in Tl2Ba2CuO6-δ single crystals with different oxygen content. Those with high critical temperature Tc>80 K have a reversible region while those with low Tc<30 K have an irreversible magnetization in the whole range of temperatures, up to Tc. The presence of the reversible region allows the formation of ordered vortex structures, while amorphous structures are obtained when no reversible region is present below Tc. The results are discussed in terms of vortex nucleation processes in the individual pinning regime.
