Specific heat and magnetic susceptibility of YBa2Cu3O7 at the superconducting transition

✍ Scribed by A. Junod; K.-Q. Wang; E. Janod; G. Triscone; J. Muller

• Publisher: Elsevier Science
• Year: 1994
• Tongue: English
• Weight: 156 KB
• Volume: 194-196
• Category: Article
• ISSN: 0921-4526
• DOI: 10.1016/0921-4526(94)91247-5

✦ Synopsis

In order to investigate the nature of the superconducting transition of YBa2Cu307, polycrystalline samples with calorimetric transition widths of 0.4 to 0.5 K were selected. Their specific heat was measured with 0.01% resolution and 0.5% accuracy. The models used to analyze the data from To/2 to 2T c, omitting a window of ±IK about To, incorporate a three-peaks phonon spectrum and a mean-field jump. We find that a model including critical fluctuations with a critical exponent of-~0.1 fits the data to 0.014% rms, while a model featuring 2D/3D Gaussian fluctuations fits "only" to 0.047% in the same conditions. The latter model becomes however acceptable for IT/T c-11 > 0.085. The magnetic susceptibility above T c may be described equally well by critical fluctuations with an exponent of ~0.35 or by 2D/3D Gaussian fluctuations.