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arXiv · 2406.07027

Inverse melting and re-entrant transformations of the vortex lattice in amorphous Re6Zr thin film

Rishabh Duhan·Subhamita Sengupta·John Jesudasan·Somak Basistha·Pratap Raychaudhuri
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Abstract

Melting of a solid is one of the most ubiquitous phenomena observed in nature. Most solids, when heated, melt from a crystalline state to an isotropic liquid at a characteristic temperature. There are however situations where increase in temperature can induce a transition to a more ordered state. Broadly termed as "inverse melting", experimental realisations of such situations are rare. Here, we report such a phenomenon in the 2-dimensional vortex liquid that forms in a moderately pinned amorphous Re6Zr (a-ReZr) thin film, from direct imaging of the vortex lattice using a scanning tunnelling microscope. At low temperature and magnetic fields, we find that the vortices form a "pinned liquid" , that is characterised by a low mobility of the vortices and vortex density that is spatially inhomogeneous. As the temperature or magnetic field is increased the vortices become more ordered, eventually forming a nearly perfectly ordered vortex lattice. Above this temperature/magnetic field, the ordered vortex lattice melts again into a vortex liquid. This re-entrant transformation from a liquid to solid-like state and then back to a liquid also leaves distinct signature in the magnetotransport properties of the superconductor.

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Rishabh Duhan, Subhamita Sengupta, John Jesudasan, Somak Basistha, Pratap Raychaudhuri. 2024-06-11. Inverse melting and re-entrant transformations of the vortex lattice in amorphous Re6Zr thin film. https://doi.org/10.1038/s41467-025-57431-3

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