• 75.50.Kj;
  • 75.60.Ch;
  • 75.60.Ej;
  • 75.60.Jk;
  • 75.75.+u


The dynamic (AC) switching field in the soft FeSiB bistable nucleus of the Fe77.5Si7.5B15–Co90Ni10 bi-phase microwires family has been measured over the frequency range 20 Hz to 2 kHz. Microwires with a CoNi thickness ranging between 0.5 μm and 8 μm were studied. Results are well fitted by a power law dependence of the switching field H * on magnetic field frequency f. As the thickness of the harder CoNi outer shell is increased, the parameters which characterise the best fit experience noticeable changes. The origin of such behaviour is interpreted in terms of modifications in the soft FeSiB nucleus domain structure, accordingly to previous established models. (© 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)