Ac susceptibility of the superconducting porous glass/Ga-In-Sn nanocomposite

Abstract

Interest to studies of gallium alloys increased recently in relation totheir prospective applications for self-healing superconducting connectionsand wires. Special attention is focused on superconductive properties ofnanostructured alloys. In the present work we studied the ac susceptibilityof a porous glass/Ga-In-Sn nanocomposite within the temperature range from1.9 to 8 K at bias fields up to 5 T. Two superconducting phase transitionswere revealed with temperatures of 5.6 and 3.1 K. Phase diagrams werecreated. Positive curvature of the parts of critical lines was demonstratedand treated within the framework of a proximity effect model. Vortexactivation barriers were found from shifts of the maxima of the imaginaryparts of susceptibility with changing the ac frequency. A bend was shown onthe field dependence of the activation barriers. Keywords: Ga-In-Sn triple alloy, nanocomposite, superconductivity, magnetometry.\

Magnetic Studies of Superconductivity in the Ga-Sn Alloy Regular Nanostructures

“…The results of fitting are shown in Figure 4 , by solid lines. Note that the model [ 16 ] was used successfully to treat the positive curvature of the upper critical-field line for some other metals and alloys within nanopores [ 7 , 13 ].…”

“…Being nanostructured as a result of embedding into nanoporous templates, the gallium-based alloys are expected to show remarkable changes in their superconducting features, as was found for pure gallium, binary Ga-Ag and triple Ga-In-Sn alloys [ 12 , 13 , 14 ]. In the particular case of the binary Ga-Sn alloy, superconductivity was studied only in bulk [ 15 ].…”

Ga-In Alloy Segregation within a Porous Glass as Studied by SANS

“…The structure of segregates can be also influenced by size effects as was demonstrated for the Ge-Sn nanoparticles which solidified under specific conditions into an amorphous phase in contrast to the bulk alloy [13]. Recent studies of superconductivity in some gallium-based eutectic alloys confined to nanoporous templates revealed strong changes in the temperature of the superconducting transitions [14][15][16].…”