The Temperature Echo of the Superconducting Phase Transition

V. N. Naumov; G. I. Frolova; T. Atake; V. V. Nogteva; N. A. Nemov; M. A. Bespyatov; V. G. Potemkin

paper

The Temperature Echo of the Superconducting Phase Transition

arXiv:cond-mat/0412679

Abstract

An analysis of experimental heat capacity at $T > T_{c}$ is presented for series of samples $(R) B a_{2} C u_{3} O_{6 + x}$ (with $x$ close to optimal). For all samples the anomaly was discovered which occurred steadily in the interval 250-290 K (anomaly $T_{h}$ ). The anomaly $T_{h}$ looks like a phase transition anomaly. It was shown that the anomaly $T_{h}$ correlates with superconducting anomaly $T_{c}$ , temperatures $T_{h}$ and $T_{c}$ being connected by the ratio $T_{h} \approx 3 T_{c}$ . The anomaly $T_{h}$ is interpreted as the origination of pairing the charge carriers. Anomalies at $T \approx 3 T_{c}$ were also detected in heat capacity of low temperature superconductors $H g$ and $N b_{3} G e$ .

6 pages, 10 figures, revtex4