Paraconductivity of planes and chains in YBa2Cu3O6.9

✍ Scribed by Bertrand Billon; Robert Gagnon; Louis Taillefer

• Publisher: Elsevier Science
• Year: 1994
• Tongue: English
• Weight: 170 KB
• Volume: 235-240
• Category: Article
• ISSN: 0921-4534
• DOI: 10.1016/0921-4534(94)92180-6

✦ Synopsis

We present results for the fluctuation-induced paraconductivity in YBa2Cu3Os.9 observed in the range Tc<T4130K. For the conductivity along the a-direction, we find that the deviation from the perfectly linear behaviour of p(T) (above 130K) cannot be described by the standard models [Aslamasov-Larkin (AL), Lawrence-Doniach (LD), Maki-Thompson]. Empirically, the measured excess conductivity exhibits two regimes in T-Tc , respectively 1-7K and 7-35K, each displaying a different power-law. The paraconductivity along the baxis is less pronounced, pointing to an effect of the CuO chains. Using a simple model of parallel conduction in the planes and along the chains, we obtain a well-defined fluctuation regime for the chain conauctivity, most likely caused by proximity effect. The impact of fluctuations on the chains is noticeable only below lOOK, roughly where the plane paraconductivity changes regime, supporting the view of a 2D to 3D crossover.