Segmented magnetic nanowires are a promising route for the development of three dimensional data storage techniques. Such devices require a control of the coercive field and the coupling mechanisms between individual magnetic elements. In our study, we investigate electrodeposited nanomagnets within host templates using vibrating sample magnetometry and observe a strong dependence between nanowire length and coercive field (25 nm to 5 μm) and diameter (25 nm to 45 nm). A transition from a magnetization reversal through coherent rotation to domain wall propagation is observed at an aspect ratio of approximately 2. Our results are further reinforced via micromagnetic simulations and angle dependent hysteresis loops. The found behavior is exploited to create nanowires consisting of a fixed and a free segment in a spin-valve like structure. The wires are released from the membrane and electrically contacted, displaying a giant magnetoresistance effect that is attributed to individual switching of the coupled nanomagnets. We develop a simple analytical model to describe the observed switching phenomena and to predict stable and unstable regimes in coupled nanomagnets of certain geometries.
@article{arxiv.1612.00314,
title = {Intra-wire coupling in segmented Ni/Cu nanowires deposited by electrodeposition},
author = {Philip Sergelius and Ji Lee and Olivier Fruchart and Mohamed Salem and Sebastian Allende and Robert Escobar and Johannes Gooth and Robert Zierold and Jean-Christophe Toussaint and Sebastian Schneider and Darius Pohl and Bernd Rellinghaus and Sylvain Martin and Javier Garcia and Heiko Reith and Anne Spende and Maria Toimil-Molares and Dora Altbir and Russel Cowburn and Detlef Görlitz and Kornelius Nielsch},
journal= {arXiv preprint arXiv:1612.00314},
year = {2017}
}