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

In this paper, we briefly described how to use the vector or biaxial vibrat ing sample magnetometer (VSM) to determine the angular dispersion of easy a xis in a magnetically soft film. For each angle of rotation phi of the exte rnal field H, a pair of the M-x-hysteresis and M-y-hysteresis loops could b e obtained. Then, we changed the phi setting from negative to positive, wit h phi=0 degrees indicating the exact direction of the hard axis of the film . Note, the easy axis has been induced by a deposition field h during fabri cation of the film. From the characteristics of the M-x-hysteresis and M-y- hysteresis loops, the condition parallel to phi parallel to <phi(c)congruen t to 1 degrees defines the "in-center zone," and the condition parallel to phi parallel to >phi(c) defines the "off-center zone." The types of switchi ng modes for the in-center and off-center zones, respectively, are differen t. Only the hysteresis behaviors in the latter zone are understood well for detailed explanations. Then, the normalized change Delta M-y/M-S due to th e wall motions at the switching field parallel to H parallel to=H-SW can be used to indicate the angular dispersion Delta theta in the film. Co70Fe10N i20 films were made with various deposition conditions in order to cause di fferent degrees of dispersion in them. The result shows that it is possible to study the angular dispersion in a magnetically soft film via the vector ial VSM measurements. (C) 2000 American Institute of Physics. [S0021-8979(0 0)02912-1].