Local magnetic properties and micromagnetic structure of FeCuNbSiB amorphous microwires

Studies of the local magnetic properties and near-surface micromagnetic str ucture 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 o ut employing a magneto-optical micro-magnetometer. The as-cast wires were a morphous. The annealed wires exhibited an ultra-fine structure with a grain size of 10-12 nm. A strong inhomogeneity of the near-surface magnetic prop erties of the as-cast samples was found. This was explained by the dispersi on of the magnetic anisotropy, which is a typical phenomenon for as-cast am orphous materials. Nanocrystalline phase formation in the annealed wires wa s found to lead to an improvement in their soft magnetic properties and a s ignificant increase in the homogeneity of the magnetic characteristics. The magnetic field behaviour of the near-surface magnetization components allo ws us to conclude that there is a curling mode of the magnetization reversa l in the examined microwires. (C) 2001 Elsevier Science B.V. Ail rights res erved.