Thermal fluctuations and vortex melting in the classical superconductor Nb3Sn from high-resolution specific-heat measurements

Abstract

The range of critical thermal fluctuations in classical bulk superconductors is extremely small and especially in low fields hardly experimentally inaccessible. With a new type of calorimeter we have been able to resolve a small lambda anomaly within a narrow temperature range around the Hc2 line. We show that the evolution of the anomaly as a function of magnetic field follows scaling laws expected in the presence of critical fluctuations. The lower onset of the fluctuation regime shows many characteristics of a continuous solid-to-liquid transition in the vortex matter. It can be driven into a first-order vortex melting transition by a small AC field which helps the vortex matter to reach equilibrium.

12 pages, 5 figures new extended version, more figures added, more detailed discussion about the vortex melting transition

References in corpus (1)

• Exploring metastability via the third harmonic measurements in single crystals of $2H$-$NbS{e}_2$ showing anomalous Peak effect

Cited by in corpus (5)

• Vortex phase dynamics in yttrium superhydride YH${}_6$ at megabar pressures
• Vortex-lattice melting and paramagnetic depairing in the nematic superconductor FeSe
• The Absence of Vortex Lattice Melting in a Conventional Superconductor
• Magnetocaloric Studies of the Peak Effect in Nb
• Magnetic field induced enlargement of the regime of critical fluctuations in the classical superconductor V3Si from high-resolution specific heat experiments