Superconductivity in Sn nanocomposites

Abstract

An ac magnetization technique was used to study superconductivity in tin loaded nanoporous silica matrices, opal matrix and two porous glasses. The behavior of type-II superconductors with a sharp transition at zero bias field was observed. Regular increase in the superconducting temperature up to 4.2 K and in a critical field up to H c2 (0) ∼ = 54 kOe with decreasing pore size was found. A crossover from the upturn to the common downturn curvature in the H c2 (T) line was seen for all nanocomposites; the upturn curvature was more pronounced for the matrix with the finest pores.

Quasireentrant superconductivity and enhanced critical field in thick Pb‐SiO2 granular films

“…Recently, He and his co‐workers studied the Pb nanowire arrays in 6 nm pores of mesoporous silica crystal matrices and an upper critical field exceeding 15 T was observed . Although enhancements of upper critical field were also observed in Pb, Al, Nb, and Sn granular films , the magnitudes of enhancement are much lower than that in Pb nanowire arrays. As the magnitude of the upper critical field is inversely proportional to the product of the coherence length and mean‐grain size a , it is interesting to investigate whether the composites of Pb nanoparticles embedding in insulator matrix possess high upper critical field.…”

Analog of the intertype superconductivity in nanostructured materials

“…This critical field is the same as for bulk tin [17]. The smaller tin particles are the type-II superconductor: the upper critical field H c2 reaches 0.15 T and 5.4 T for particles with the size of 58 nm and 8 nm correspondingly [10].…”

“…Arrays of nanowires with various sizes open up perspectives for composite superconducting materials with variable magnetic properties [8]. Recently, methods have been developed to produce nanostructured superconductors with a structural element size of ~ 10-100 nm [9][10][11][12][13][14][15]. Values of ξ, λ and κ differ for nanostructured and bulk superconductors [10,11,16].…”

“…Recently, methods have been developed to produce nanostructured superconductors with a structural element size of ~ 10-100 nm [9][10][11][12][13][14][15]. Values of ξ, λ and κ differ for nanostructured and bulk superconductors [10,11,16]. Thus, tin particles with the size of 120 nm are the type-I superconductor with μ 0 H c (0) ≈ 0.03 T [13].…”

Динамическая восприимчивость нанокомпозита пористое стекло/Ga-In-Sn в области сверхпроводимости

“…Недавние исследования нанокомпозитов на основе пористых матриц, заполненных сверхпроводящими металлами, выявили ряд общих закономерностей на фоне индивидуальных различий, связанных с размером пор, связностью сверхпроводящей фазы и морфологией сверхпроводящих включений [5][6][7][8][9][10][11][12]. Наноконфайнмент приводит к изменению рода сверхпроводимости за счет уменьшения длины когерентности, а также к возрастанию значений верхнего критического поля и критического тока.…”