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arXiv · 0902.1086

Evidence for Kosterlitz-Thouless and 3D-xy critical behavior in Bi2212

S. Weyeneth·T. Schneider·E. Giannini
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Abstract

We present reversible magnetization data of a high quality Bi2212 single crystal and explore the occurrence of 3D-xy critical behavior close to the bulk transition temperature Tc and of Kosterlitz-Thouless (KT) behavior. Below and above the presumed Kosterlitz-Thouless transition temperature T_KT we observe the characteristic 2D-xy behavior: a downward shift of the crossing point phenomenon towards T_KT as the field is decreased and sufficiently below T_KT the characteristic 2D-xy relationship between the magnetization an the in-plane magnetic penetration depth. In contrast, the measured temperature dependence of the superfluid density does not exhibit the characteristic KT-behavior around the presumed T_KT. The absence of this feature is traced back to the 2D- to 3D-xy crossover setting in around and above T_KT. Invoking the Maxwell relation the anomalous field dependence of the specific heat peak is also traced back to the intermediate 2D-xy behavior. However, close to Tc we observe consistency with 3D-xy critical behavior, in agreement with measurements of the in-plane magnetic penetration depth.

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S. Weyeneth, T. Schneider, E. Giannini. 2009-04-17. Evidence for Kosterlitz-Thouless and 3D-xy critical behavior in Bi2212. https://doi.org/10.1103/physrevb.79.214504

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