Attractive Interaction between Vortices in Nb

Temperature dependence of clusters with attracting vortices in superconducting niobium studied by neutron scattering

“…The large value of Q 2 implies an attractive interaction between the flux The corresponding periodicity, d 2 = 2π/Q 2 , can be interpreted as the upper limit for the lattice spacing as expected in this regime [32]. A similar conclusion was reported from the analysis of the induction jump at B c1 in a (pinning-free) low κ superconductor with highly reversible magnetization [33][34][35][36] and from a neutron diffraction experiment for temperatures close to 4 K [8,31]. Figure 7 shows the corresponding lattice periodicity d 2 as a function of temperature, independent of the applied field up to 200 G. The value d 2 = 1660 Å measured at 4 K is in good agreement with the values reported by Schelten et al (≈1800 Å) and Mühlbauer et al (≈1600 Å) [8,31].…”

“…The corresponding periodicity, d 2 = 2π/Q 2 , can be interpreted as the upper limit for the lattice spacing as expected in this regime [32]. A similar conclusion was reported from the analysis of the induction jump at B c1 in (pinning free) low κ superconductor with highly reversible magnetization [33][34][35][36] or from neutron diffraction experiment for temperature close to 4 K [8,31]. Fig.…”

Surface superconductivity in niobium and niobium-tantalum alloys

“…(Figure 50). The data obtained here are in general agreement with the data obtained by Finnemore et £]_ (35,58)…”