Series of maxima in the field dependent magnetic moment of layered superconductors

Abstract

Magnetic moment measurements on niobium/copper multilayers by means of a torque magnetometer exhibit a series of maxima at specific field strengths ${\mathit{H}}_{\mathit{N}}$ when the applied magnetic field makes a small angle with the plane of the superconducting layers. These maxima are shown to be closely related to rearrangements of the parallel vortex system, during which an increasing number of vortex chains is formed in the sample.