Self consistent measurement and removal of the dipolar interaction field in magnetic particle assemblies and the determination of their intrinsic switching field distribution

Abstract

Using low density arrays of bistable magnetic nanowires as a model dipolar system, it is shown that the dipolar interaction field coefficient can be measured from the remanence curves as well as from other functions of the isothermal remanent magnetization and the DC demagnetization remanence obtained as an affine transformation of the Wohlfarth relation. Based on mean field arguments, these measurements are used to subtract and remove the contribution of the configuration dependent dipolar interaction field from the major loop and remanence curves. The corrected remanence curves are first used to obtain the intrinsic switching field distribution of the nanowire array and then to validate this approach showing that they yield results consistent with the Wohlfarth relation for an assembly of noninteracting particles, thus providing a self-consistent procedure to verify the measured values of the interaction field and its removal from the measurements.