Remanent magnetic measurements on perpendicular recording materials with compensation for demagnetizing fields

Abstract

Existing techniques for characterization of longitudinal recording media using remanence measurements are extended to perpendicular media, in particular to Alumite, and correction for demagnetizing fields is taken into account. It is found that these techniques have limited value because of the sensitivity of the analysis to the correction factor used. Measurement of the recoil lines is investigated as an alternative method of probing the reversal processes.

The interaction field in arrays of ferromagnetic barcode nanowires

“…This geometric transformation is performed under the assumption that the interaction field is proportional to the total magnetization of the sample [34,36]. Therefore the identification of the interaction field in arrays of magnetic nanowires requires information about magnetization processes in individual nanowires, distributions of switching fields and overall magnetization loops of the arrays [35]. In the following, we describe how these requirements have been addressed from a theoretical point of view, the results obtained from experimental measurements being presented in section 4.…”

“…Firstly, non-interacting loops of these arrays are obtained by linear superpositions of magnetization processes in individual ferromagnetic segments (considered as hysterons [34]). Then, overall hysteresis loops of interacting nanowires are obtained by simple linear transformation of the non-interacting ones into the operative Preisach plane [34,35]. This geometric transformation is performed under the assumption that the interaction field is proportional to the total magnetization of the sample [34,36].…”

On the ability to determine intrinsic switching field distributions from hysteresis loops in the partially correlated magnetization reversal regime

“…where J(M) is typically a single valued non-linear function [19]. The local fields acting on grains are then obtained by calculating the variation of G MF with respect to M and are equal to…”

Educational software for the numerical correction of experimental magnetization curves

“…Indeed, the edges of the magnetic circuit gap [10] or the cutting edges of the sample [11] can influence the local magnetic field. The high-frequency measurement of high-permeability materials in strip-line resonant cavities [12] or the remanent magnetic measurement on perpendicular recording media [13] must be also corrected, even a thinfilm sample is used. This probe positioning introduces supplementary measurement noise for mobile coil type measurement, e.g.…”