A toolbox for convenient calculation of anisotropy of magnetic remanence

The growing interest in ferromagnetic fabric, i.e. magnetic fabric carried solely by ferromagnetic (sensu lato) grains, creates the need for a simple way to obtain anisotropy of magnetic remanence (AMR) tensors from a set of laboratory imparted, spatially distributed vectors of remanent magnetization (RM). Here, we present a simple, user-friendly toolbox embedded into Anisoft software which facilitates AMR tensor fitting from an array of RM vectors acquired according the prescribed data acquisition protocol (6, 9, 12, 15, 18 magnetizing directions). As these protocols are usually quite laborious involving a series of demagnetizations and directional magnetizations, this toolbox provides a graphical visualization of the measured RM vectors in terms of their directional comparison with the respective magnetizing directions and their intensity in comparison with the intensity of demagnetized state (background magnetization). This visualization provides a convenient way to check whether there are no evident missteps and the measured vectors correspond to the acquisition protocol. Prior to tensor fitting, the correction for the background magnetization is optionally done by a direct subtraction of the measured background or by mutual subtraction of antipodally magnetized RM vectors, if available. The AMR tensors are fitted by the least-square algorithm using two slightly different approaches involving either (1) all three orthogonal components of magnetized RM vectors (Vector Method) or (2) their projections to the respective magnetizing directions (Projection Method). The differences between these two approaches are discussed. The calculated AMR tensors, including their confidence limits, are stored in the same file format as AMS data and can be thus instantly visualized and further processed using Anisoft software.