Traditional methods of magnetic domain control, such as applying external magnetic fields or currents, struggle to achieve precise manipulation at the microscale. This new "magnetic domain paper-cutting" technique leverages the magnetoelastic coupling effect, which is the interaction between a material's magnetic and elastic properties. By etching nanotrenches into permalloy/poly(methyl methacrylate) bilayers, tensile stress within the film can be directionally released, guiding the arrangement of magnetic domains.
Methods
The researchers first fabricated nanotrench patterns on a poly(methyl methacrylate) film and then deposited a permalloy film on top. Using electron beam lithography, they precisely controlled the shape and arrangement of the trenches. Through magnetic force microscopy (MFM) and hysteresis loop measurements, they observed the magnetic domain arrangement and macroscopic magnetic property changes under different patterns.
Directional arrangement of magnetic domains: The nanotrenches directionally release tensile stress, guiding the magnetic domains to align along the trench direction. Formation of magnetic disclinations: Two-dimensional closed boundaries induce curved stripe domains, which ultimately transform into disclinations. Controllability of magnetic disclinations: The geometric configuration and arrangement of disclinations can be adjusted by altering the shape, size, and arrangement of the two-dimensional boundaries.
This study provides a simple, efficient, and highly designable method for manipulating magnetic domains, with potential applications in spintronics and information storage. For example, information could be stored by controlling the arrangement of magnetic disclinations, or the topological properties of disclinations could be used to design novel spintronic devices.
Fig. 1. Formation of magnetic disclinations by inserting grooves along the y-direction, as marked by the yellow frames. The lengths of grooves (g) are a) 0, b) 0.8, c)1.1, and d) 1.5 μm. Corresponding magnetic hysteresis loops (M/Ms vs. H) of the Py microstructures with increasing g under e) Hₓ and f) Hᵧ.
The first author of this work is Prof. Li-Zhong Zhao from Hangzhou Dianzi University. Dr. Rong-Zhi Zhao and Prof. Jian Zhang from Hangzhou Dianzi University are the corresponding authors of this paper.
