Controlling degeneracy and magnetization switching in an artificial spin ice system of peanut-shaped nanomagnets

TL;DR

This study uses numerical simulations to explore magnetization switching and state degeneracy control in a novel artificial spin ice system with peanut-shaped nanomagnets, revealing lower switching fields and monopole-like states.

Contribution

It introduces a new ASI design with peanut-shaped nanomagnets, demonstrating controllable degeneracy and reduced switching fields compared to traditional geometries.

Findings

Switching field is an order smaller than conventional systems.

Metastable 2-in/2-out states are robust at remanence.

Defect-induced charge neutrality breaking leads to monopole-like states.

Abstract

Using extensive numerical simulations, we probe the magnetization switching in two-dimensional artificial spin ice (ASI) system consisting of peanut-shaped nanomagnets. We also investigated the effect of the external magnetic field on the degeneracy of the magnetic states in such a system. The switching field is found to be one order smaller in the proposed ASI system with peanut-shaped nanomagnets as compared to the conventionally used highly-anisotropic nanoisland such as elliptically shaped nanomagnets. The metastable 2-in/2-out (Type II) magnetic state is robust at the remanence. We are also able to access the other possible microstates corresponding to Type II magnetic configurations by carefully varying the external magnetic field. It implies that one can control the degeneracy of the magnetic state by the application of a suitable magnetic field. Interestingly, the magnetic charge neutrality breaks due to the defects induced by removing nanomagnets. In such a case, the system also appears to have a 1-out/3-in or 3-out/1-in (Type III) spin state, reminiscent of a magnetic monopole. We believe that our study is highly desirable in the context of developing the next-generation spintronics-based devices for future technologies.