Study of the magnetic anisotropy of micron-sized CoFeSiB glass covered amorphous wires

Abstract

In this study, the magnetic properties of CoFeSiB glass covered amorphous wires (GCAWs) concerning their anisotropy, susceptibility, and coercivity have been investigated. The microscopic hysteresis loops of GCAWs of different lengths ranging from 1 to 40 mm and different metallic diameters ranging from 7 to 30 μm, fabricated by the Taylor-Ulitovsky method, were measured using the induction method. The results showed that the anisotropy of the GCAWs depends on the coupling of magnetostriction and internal stresses, and can be tailored by varying the ratio of the glass coating layer thickness to the metal core radius because the ratio characterizes the stress in the ferromagnetic core. The larger the ratio, the smaller the angle between the easy axis of anisotropy and the circumferential direction. The results further showed that for a GCAW wire originally with helical anisotropy, shortening the length of the wire below a critical value -10 mm will change the anisotropy from helical to circumferential, because the wire end domains form circumferential anisotropy. © 2011 American Institute of Physics.