Improving information storage by means of segmented magnetic nanowires

A set of magnetic nanowires trapped in the membrane used to produce them can be employed to inscribe information in the form of sectors of wires with the same ferromagnetic orientation (Cisternas and Vogel, 2013 [1]). However, such a system relays on the shape anisotropy of each nanowire as the stabilizing mechanism avoiding magnetization reversal. Such stabilization mechanism weakens as the size of the nanowires decrease. In the present paper we introduce a way of using segmented nanowires to produce a self-stabilization mechanism based on the fact that interactions among segments of different layers can contribute with negative energies. Then, for some particular geometries it is possible to make this interaction the most important one producing a more stable system with respect to spontaneous magnetization reversal. Such inscribed ferromagnetic sector will then last longer than other ferromagnetic sectors formed by exclusively repelling elements. We make use of available algebraic expressions to calculate the energy contribution of noncoaxial segments. For the coaxial segments a similar expression is developed here and it is applied to real systems. The total interaction energy for all segments in the system is calculated for different geometrical possibilities. Application to two particular symbols (letters T and O) is fully discussed bringing out general aspects that could be applied to other symbols. Projections of this work are finally mentioned. (C) 2015 Elsevier B.V. All rights reserved.