Understanding magnetotransport signatures in networks of connected permalloy nanowires

TL;DR

This paper investigates the complex magnetoresistance behavior in connected networks of ferromagnetic nanowires, specifically artificial spin ice, through experiments and simulations, revealing the importance of vertex contributions in magnetic responses.

Contribution

It introduces a simulation methodology and experimental analysis that highlight the role of vertices in magnetotransport signatures in artificial spin ice networks.

Findings

Vertex contributions are crucial for understanding low-field magnetoresistance.

Simulation results match experimental data, confirming the significance of geometry.

New geometrically-induced magnetoresistance phenomena are identified.

Abstract

The change in electrical resistance associated with the application of an external magnetic field is known as the magnetoresistance (MR). The measured MR is quite complex in the class of connected networks of single-domain ferromagnetic nanowires, known as "artificial spin ice", due to the geometrically-induced collective behavior of the nanowire moments. We have conducted a thorough experimental study of the MR of a connected honeycomb artificial spin ice, and we present a simulation methodology for understanding the detailed behavior of this complex correlated magnetic system. Our results demonstrate that the behavior, even at low magnetic fields, can be well-described only by including significant contributions from the vertices at which the legs meet, opening the door to new geometrically-induced MR phenomena.