Imaging the vortex-lattice melting process in the presence of disorder

Abstract : General arguments(1) suggest that first-order phase transitions become less sharp in the presence of weak disorder, while extensive disorder can transform them into second-order transitions; but the atomic level details of this process are not clear. The vortex lattice in superconductors provides a unique system in which to study the first-order transition(2-6) on an inter-particle scale, as well as over a wide range of particle densities. Here we use a differential magneto-optical technique to obtain direct experimental visualization of the melting process in a disordered superconductor. The images reveal complex behaviour in nucleation, pattern formation, and solid-liquid interface coarsening and pinning. Although the local melting is found to be first-order, a global rounding of the transition is observed; this results from a disorder-induced broad distribution of local melting temperatures, at scales down to the mesoscopic level. We also resolve local hysteretic supercooling of microscopic liquid domains, a nonequilibrium process that occurs only at selected sites where the disorder-modified melting temperature has a local maximum. By revealing the nucleation process, we are able to experimentally evaluate the solid-liquid surface tension, which we rnd to be extremely small.
Type de document :
Article dans une revue
Nature, Nature Publishing Group, 2000, 406 (6793), pp.282-287. 〈10.1038/35018532〉
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https://hal-polytechnique.archives-ouvertes.fr/hal-01068642
Contributeur : Gaëlle Bruant <>
Soumis le : vendredi 26 septembre 2014 - 09:46:38
Dernière modification le : mercredi 31 janvier 2018 - 12:13:15

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A. Soibel, Eli Zeldov, Michael Rappaport, Yuri Myasoedov, Tsuyoshi Tamegai, et al.. Imaging the vortex-lattice melting process in the presence of disorder. Nature, Nature Publishing Group, 2000, 406 (6793), pp.282-287. 〈10.1038/35018532〉. 〈hal-01068642〉

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