The low magnetic field, H, dependence of real part of impedance, R, of as-received FeSiB and CoSiB wires have been investigated. The measurements were performed at various frequencies for various wire lengths. The wires with length longer than 7cm show sharp peaks in the R-H curves. The combination of R-H data with M-H data indicates the existence of interaction between motion of the domain wall in the inner core and the magnetic moments in the outer shell. (C) 2003 Elsevier B.V. All rights reserved.