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3D-XY critical fluctuations of the thermal expansivity in detwinned YBa2Cu3O7-d single crystals near optimal doping

Volker Pasler·Peter Schweiss·Christoph Meingast·Bernhard Obst·Helmut Wuehl·Alexandre I. Rykov·Setsuko Tajima
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Abstract

The strong coupling of superconductivity to the orthorhombic distortion in YBa2Cu3O7-d makes possible an analysis of the superconducting fluctuations without the necessity of subtracting any background. The present high-resolution capacitance dilatometry data unambiguously demonstrate the existence of critical, instead of Gaussian, fluctuations over a wide temperature region (+/- 10 K) around Tc. The values of the amplitude ratio A+/A-=0.9-1.1 and the leading scaling exponent |alpha|<0.018, determined via a least-squares fit of the data, are consistent with the 3D-XY universality class. Small deviations from pure 3D-XY behavior are discussed.

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Volker Pasler, Peter Schweiss, Christoph Meingast, Bernhard Obst, Helmut Wuehl, Alexandre I. Rykov, Setsuko Tajima. 1998-04-03. 3D-XY critical fluctuations of the thermal expansivity in detwinned YBa2Cu3O7-d single crystals near optimal doping. https://doi.org/10.1103/physrevlett.81.1094

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