# Chiral anisotropic magnetoresistance of ferromagnetic helices

## TL;DR

This paper studies how the unique 3D shape and chirality of ferromagnetic helices influence their anisotropic magnetoresistance, revealing new effects related to shape and current-induced magnetic fields, with implications for device design.

## Contribution

It demonstrates the impact of helix geometry and chirality on AMR, introducing the role of self magnetic fields in magnetoresistance behavior in 3D curved structures.

## Key findings

- AMR depends on helix geometry and external magnetic field.
- Chirality influences an additional current-dependent AMR contribution.
- Self magnetic field from current alters magnetization orientation.

## Abstract

We investigate the anisotropic magnetoresistance (AMR) of ferromagnetic CoNi microhelices fabricated by electrodeposition and laser printing. We find that the geometry of the three-dimensional winding determines a characteristic angular and field-dependence of the AMR due to the competition between helical shape anisotropy and external magnetic field. Moreover, we show that there is an additional contribution to the AMR that scales proportionally to the applied current and depends on the helix chirality. We attribute this contribution to the self magnetic field induced by the current, which modifies the orientation of the magnetization relative to the current flow along the helix. Our results underline the interest of three-dimensional curved geometries to tune the AMR and realize tubular magnetoresistive devices.