Asymmetric magnetization reversal of partially devitrified Co66Si15B14Fe4Ni1

Abstract Anomalous hysteresis has been observed in annealed Co 66 Si 15 B 14 Fe 4 Ni 1 amorphous ribbons consisting of asymmetrically distorted and horizontally shifted loops. Although the magnetic hysteresis loops present remarkable similarities with those produced by exchange bias uniaxial anisotropy, this is discarded in these samples, so the comprehension of the origin of these characteristics is an interesting topic of research. Transmission electron microscopy, selected area diffraction and X-ray diffraction experiments have been carried out in order to investigate the structural properties of the samples. A very low dilution of nanocrystallites, with sizes of about 20 nm, has been detected coexisting with some bigger crystals of around 0.4–1.0 μm. The hysteretic particularities and their evolution with different magnetic treatments are then analyzed as a consequence of the dipolar interaction between the crystalline particles and the residual amorphous matrix.