Numerical study of geometrical frustration in a planar soft-hard magnetic system

We computationally study the frustrated macroscopic magnetic configurations of a thin soft-magnetic layer on top of a hard magnet geometrically patterned as three equidistant disks. The interplay between competing exchange, magnetostatic, and Zeeman interactions, enhanced by the geometric constraints, results in rich magnetization configurations when an external magnetic field is rotated around the sample. We identify four successive ranges of the external field magnitude in each of which the system exhibits unique energetics and chooses different sets of energy minima during the rotation of the external magnetic field. The system can be used as a ternary logic storage device, with read and write operations achieved by utilizing the unique behavior of the system in each of the four regimes.