Angular dispersion of the easy axis in a magnetically soft film as determined by vibrating sample magnetometry

摘要

In this paper, we briefly described how to use the vector or biaxial vibrating sample magnetometer (VSM) to determine the angular dispersion of easy axis in a magnetically soft film. For each angle of rotation φ of the external field H, a pair of the M_(x)-hysteresis and M_(y)-hysteresis loops could be obtained. Then, we changed the φ setting from negative to positive, with φ=0°indicating the exact direction of the hard axis of the film. Note, the easy axis has been induced by a deposition field h during fabrication of the film. From the characteristics of the M_(x)-hysteresis and M_(y)-hysteresis loops, the condition φφ_(c) defines the "off-center zone." The types of switching modes for the in-center and off-center zones, respectively, are different. Only the hysteresis behaviors in the latter zone are understood well for detailed explanations. Then, the normalized change △M_(y)/M_(S) due to the wall motions at the switching field H=H_(SW) can be used to indicate the angular dispersion △θ in the film. Co_(70)Fe_(10)Ni_(20) films were made with various deposition conditions in order to cause different degrees of dispersion in them. The result shows that it is possible to study the angular dispersion in a magnetically soft film via the vectorial VSM measurements.