Anomalous matching effect and attractive vortex interaction in 7.5-μm triangular microhole lattice on Pb film

Abstract

It is considerably exciting to explore the novel vortex physics in multiply connected superconductors. We prepare triangular microhole lattice on Pb film (TriMHoLP) by evaporation of a type-I superconductor Pb upon a capillary plate (6-μm hole and 7.5-μm pitch) in vacuum. We measure the magnetization of TriMHoLP in the RSO mode under low fields (| H|⩽4.7 G). The polarity of magnetization peaks is identical against the field reversal. The magnetization curves as a function of temperature taken in a field-cooling mode of RSO are always positive irrelevant to the field polarity. We show that a vortex–vortex interaction is not always repulsive in a low- κ superconductor. We consider that a spontaneous magnetization and an anomalous matching effect near T c are relevant to the attractive interaction between vortices.