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Soutenance de thèse de Juan Trastoy Quintela

Juan Trastoy Quintela soutiendra sa thèse intitulée "Efficient artificial ordered vortex pinning in high-TC superconductors via masked ion irradiation" à l’auditorium de Thales-RT.


  • Vendredi 5 décembre 2014 14:00-17:30 - Juan Trastoy Quintela - Unité Mixte de Physique CNRS/Thales

    Soutenance de thèse de Juan Trastoy Quintela

    Résumé : Superconducting flux quanta in nanostructured YBa2Cu3O7-δ films constitute a model to study the general problem of interacting particles in a potential-energy landscape. Using O+ ion irradiation through a mask defined via electron-beam lithography, ordered nanometric regions with a depressed local critical temperature can be defined to precisely engineer the vortex energy landscape. A detailed characterization of this artificial pinning’s strength with temperature and vortex velocity is given, as well as a study of the vortex phase diagram and the associated thermodynamic phase transition. Thanks to the ability to modulate the superconducting condensate at the nanoscale, a new mechanism to reversibly switch the vortex energy landscape’s geometry using temperature as a control knob is developed. This is shown through the thermal switching of a geometrically frustrated array into a square periodic one. Finally, asymmetric vortex motion under a symmetric drive is studied using asymmetric pinning sites.

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