Manipulation of the magnetic monopole injection for topological transition

Abstract

Manipulating the topological properties of spin textures in magnetic materials is of great interest due to the rich physics and promising technological applications of these materials in advanced electronic devices. A spin texture with desired topological properties can be created by magnetic monopole injection, resulting in topological transitions involving changes in the topological charge. Therefore, controlling magnetic monopole injection has paramount importance for obtaining the desired spin textures but has not yet been reported. Here, we report the use of reliably manipulated magnetic monopole injection in the topological transition from stripe domains to skyrmions in an Fe/Gd multilayer. An easily tunable in-plane magnetic field applied to an Fe/Gd multilayer plays a key role in the magnetic monopole injection by modulating the local exchange energy. Our findings facilitate the efficient management of topological transitions by providing an important method for controlling magnetic monopole injection. In the nanomagnetism realm, scientists are intrigued by minuscule magnetic formations known as spin textures, possessing unique characteristics that could transform electronic devices. However, there's a knowledge gap in controlling these structures' transformation, especially creating stable formations called skyrmions. In a recent study, Mi-Young Im and team devised a technique to control the injection of a magnetic monopole a crucial step in forming skyrmions, in a ferrimagnetic multilayer film. They performed experiments and simulations demonstrating that a slight in-plane magnetic field can focus energy favoring MP injection, leading to skyrmion formation. The results indicated that the controlled injection of MPs is vital for the topological transition from stripe domains to skyrmions. The study concludes that the strength of the in-plane magnetic field is a critical factor in this process, offering a new method to manipulate magnetic structures for advanced technologies. This summary was initially drafted using artificial intelligence, then revised and fact-checked by the author. Topological transition of a bubble to a skyrmion by the controlled magnetic monopoles injection in Fe/Gd magnetic multilayers. The magnetic monopoles injected from the top and bottom surfaces are topologically characterized by Q = -1 and Q = +1, respectively.