Artificial helical nanomagnets

TL;DR

This paper reports the creation and confirmation of stable helical magnetic states in patterned multilayer nanomagnets, which are composed of ferromagnetic disks separated by spacers, demonstrating potential for room-temperature applications.

Contribution

It introduces artificial helical nanomagnets with a stable spiral state originating from magnetostatic interactions, fabricated from multilayer structures using electron beam lithography.

Findings

Helical states are stable at room temperature.

Magnetic force microscopy confirms the spiral configuration.

Magnetostatic interactions drive the formation of the helix.

Abstract

We demonstrate the existence of a helical state in patterned multilayer nanomagnets. The artificial helimagnets consist of a stack of single domain ferromagnetic disks separated by insulating nonmagnetic spacers. The spiral state is shown to originate from the magnetostatic interaction between nearest and next nearest neighbouring single-domain disks in the stack. Since the magnetostatic interaction for such disks is rather strong, the helical state should be stable at room temperature. The helimagnets were fabricated from a [Co/Si]*3 multilayer using electron beam lithography. The helical state was confirmed by a magnetic stray field analysis using magnetic force microscopy.