Local magnetic properties and micromagnetic structure of FeCuNbSiB amorphous microwires

Abstract

Studies of the local magnetic properties and near-surface micromagnetic structure of as-cast and annealed (550 degreesC for 1 h) Fe73.5Cu1Nb3Si13.5B9 amorphous microwires with a magnetic core of 10-mum diameter were carried out employing a magneto-optical micro-magnetometer. The as-cast wires were amorphous. The annealed wires exhibited an ultra-fine structure with a grain size of 10-12 nm. A strong inhomogeneity of the near-surface magnetic properties of the as-cast samples was found. This was explained by the dispersion of the magnetic anisotropy, which is a typical phenomenon for as-cast amorphous materials. Nanocrystalline phase formation in the annealed wires was found to lead to an improvement in their soft magnetic properties and a significant increase in the homogeneity of the magnetic characteristics. The magnetic field behaviour of the near-surface magnetization components allows us to conclude that there is a curling mode of the magnetization reversal in the examined microwires. (C) 2001 Elsevier Science B.V. Ail rights reserved.