Phase transition in the vortex liquid and the critical endpoint in YBa2Cu3Oy

Kenji Shibata, Terukazu Nishizaki, Takahiko Sasaki, Norio Kobayashi

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60 Citations (Scopus)


The vortex phase diagram of optimally doped untwinned YBa2Cu3Oy is studied. We find a first-order transition TL(H) in the vortex liquid above the terminal point Hmcp (≃7 T) of both the vortex glass line Tg(H) and the field-driven disordering transition line H*(T). The obtained small entropy change (∼0.02 kB/vortex/layer) and the critical endpoint Hcep (≃11 T) of the TL(H) line indicate that the vortex liquid undergoes the vortex slush regime before the solidification into the vortex glass phase. Below Hmcp, the vortex liquid phase shows the first-order melting transition into the Bragg glass phase. We also study the oxygen content y dependence of the vortex phase diagram and find that the vortex slush regime is located in the borderline (i.e., 6.90≤y≤6.92) below which the vortex lattice melting transition disappears. The result indicates that the point disorder with the intermediate strength plays an important role in the vortex slush regime.

Original languageEnglish
Article number214518
Pages (from-to)2145181-2145187
Number of pages7
JournalPhysical Review B - Condensed Matter and Materials Physics
Issue number21
Publication statusPublished - 2002 Dec 1

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics


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