Fourfold nanosystems for quaternary storage devices

In nano-magnetic coupled systems of wires, pronounced magnetization steps in the hysteresis loops have been found by micromagnetic simulations. The steps can be attributed to stable intermediate states, similar to flux-closed vortex states in ferromagnetic nano-rings. Due to the fourfold anisotropy of the system of four crossed nanowires, these states can be distinguished even by measuring the magnetization of the whole system, giving rise to four separated states without application of external magnetic field. Opposite to actual trials with nano-rings or layered structures, no additional method of symmetry breaking is necessary. Such an easily created system can be utilized, e.g., in quaternary (four states, i.e., two bits per magnetic nano-object) magnetic storage applications.