Disorder-induced Kinetic arrest in the Vortex melting transition of a type-II Superconductors

FASANO, YANINA

Buenos Aires

Workshop; Invited talk at the 3rd Workshop on the Structure and Dynamics of Glassy, Supercooled and Nanoconfined fluids; 2019

Tandar, CNEA

First order phase transitions (FOT) are ubiquitous in nature, including structural, magnetic, electric and electronic transformations with a discontinuous entropy-change and its associated latent heat. In real experimental systems, the unavoidable quenched disorder affects the thermodynamic properties of FOT. Even a slight amount of disorder can produce a rounding of the FOT entailing a depletion of the latent heat.~\cite{Imry79} Contrasting this rounding prediction with experimental results is challenging since the unavoidable static finite size and dynamic kinetic arrest effects smear an unified description for a wide variety of condensed matter systems. Although no general picture is still available, most condensed-matter systems share the stabilization of glassy phases on increasing disorder.~\cite{Mydosh} Vortex matter in type-II superconductors is a model system to study how on increasing the disorder strength, density, and spatial correlation, a FOT in pristine samples can mute to a continuous second ordertransformation or even a crossover line. We study vortex matter in the high--temperature Bi$_{2}$Sr$_{2}$CaCu$_{2}$O$_{8+\delta}$ superconductorwith correlated disorder in the form of a low dose of columnar defects, focusing on the changes induced in the FOT vortex melting transition on increasing disorder. We use dc and ac local Hall magnetometry to track the melting temperature and entropy-jumps. We found that the transition remains first-order up to a critical density of disorder, but for larger densities of columnar defects the transition is smeared and the typical features are frequency dependent, a phenomenology typically observed in kinetically-arrested phase transitions.