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arXiv · 1408.1445

Experimental observation of a first-order phase transition below the superconducting transition temperature in the multilayer cuprate superconductor HgBa$_2$Ca$_4$Cu$_5$O$_y$

Y. Tanaka·A. Iyo·S. Itoh·K. Tokiwa·T. Nishio·T. Yanagisawa
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Abstract

A first-order phase transition is found in the multilayer cuprate superconductor, HgBa$_2$Ca$_4$Cu$_5$O$_y$ (Hg-1245), with a superconducting transition temperature of 108 K, under zero magnetic field. We observed a hysteretic specific heat jump around 41 K. We conclude that the Bardeen-Cooper-Schrieffer pairs have a residual entropy due to fluctuations in the phase difference between the five CuO$_2$ planes in a unit cell of Hg-1245, and that this fluctuation freezes below the first-order phase transition temperature.

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Y. Tanaka, A. Iyo, S. Itoh, K. Tokiwa, T. Nishio, T. Yanagisawa. 2014-08-07. Experimental observation of a first-order phase transition below the superconducting transition temperature in the multilayer cuprate superconductor HgBa$_2$Ca$_4$Cu$_5$O$_y$. https://doi.org/10.7566/jpsj.83.074705

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