a1 Instituto de Fí’sica, Universidade Federal do Rio de Janeiro, C.P. 68528, 21945–970, Rio de Janeiro, RJ, Brasil
a2 Instituto de Magnetismo Aplicado (UCM—RENFE), Instituto de Ciencia de Materiales de Madrid (CSIC), P.O. Box 155, 28230 Las Rozas, Madrid, Spain
a3 Departamento de Fí’sicas, Universidad de Oviedo, Avenida de Calvo Sotelo s/n, 33007, Oviedo, Spain
Co90P10 amorphous microtubes with thickness ranging from 2 to 19 μm were electrodeposited onto Cu wire substrates. Samples exhibit radial magnetic anisotropy as deduced from hysteresis loops and magnetic force microscopy imaging. These microtubes show quite noticeable giant magnetoimpedance effect (GMI) with amplitude depending on layer thickness and frequency. The hysteresis in the GMI curves is small, which can be ascribed to the radial anisotropy. Such small hysteresis is of importance for technological applications.
(Received June 22 1999)
(Accepted January 06 2000)