Magnetic field driven dynamics in twisted bilayer artificial spin ice at superlattice angles

• Main Authors: Popy, Rehana Begum, Frank, Julia, Stamps, Robert L
• Format: Journal Article
• Language: English
• Published: 03-08-2022
• Subjects: Physics - Mesoscale and Nanoscale Physics
• DOI: 10.48550/arxiv.2208.02243

Geometrical designs of interacting nanomagnets have been studied extensively
in the form of two dimensional arrays called artificial spin ice. These systems
are usually designed to create geometrical frustration and are of interest for
the unusual and often surprising phenomena that can emerge. Advanced
lithographic and element growth techniques have enabled the realization of
complex designs that can involve elements arranged in three dimensions. Using
numerical simulations employing the dumbbell approximation, we examine possible
magnetic behaviours for bilayer artificial spin ice (BASI) in which the
individual layers are rotated with respect to one another. The goal is to
understand how magnetization dynamics are affected by long-range dipolar
coupling that can be modified by varying the layer separation and layer
alignment through rotation. We consider bilayers where the layers are both
either square or pinwheel arrangements of islands. Magnetic reversal processes
are studied and discussed in terms of domain and domain wall configurations of
the magnetic islands. Unusual magnetic ordering is predicted for special angles
which define lateral spin superlattices for the bilayer systems.