Non-ohmic behaviour in Tℓ-2212 films in a weak magnetic field

✍ Scribed by L. Ammor; J.C. Soret; A. Smina; B. Martinie; J. Lecomte; L. Coudrier; S. Flament; Ch. Gasser; Ch. Simon

• Publisher: Elsevier Science
• Year: 1994
• Tongue: English
• Weight: 226 KB
• Volume: 235-240
• Category: Article
• ISSN: 0921-4534
• DOI: 10.1016/0921-4534(94)92563-1

✦ Synopsis

A power law, V ~ I a, between voltage and current is reported in a TI-2212 thin film in a weak magnetic field (up to 300 mT) applied perpendicularly to the layers. We find experimental support for the existence of a phase transition depending on magnetic field, below the zero magnetic field transition Tc~ We discuss these results in terms of a defect-mediated vortex-lattice (VL) melting leading to a Berezinskii-Kosterlitz-Thouless transition type. Consistency is found with a logarithmic coupling energy U(r) = A ln(r/ro) between VL defects where the unrenormalized interaction constant A ~ T(Tco-T) 3/2/H and the Abrikosov lattice parameter sets the cut-off ro.