Trapping of a magnetic soliton by modifying the boundary conditions of a synthetic ferrimagnetic superlattice

Abstract

Vertical shift registers and 3-dimensional magnetic memory structures potentially provide a revolutionary increase in the areal density of magnetic data storage devices [1-3]. The Ruderman-Kit-tel-Kasuya-Yosida (RKKY) exchange coupled magnetic multilayer architecture proposed in [2] uses a localized topological soliton as a bit of information. The nucleation and injection of this bit, which is a form of excitation in the antiferromagnetic stack, has to be highly reproducible in order for this architecture to work [1, 4]. The nucleation and subsequently the propagation of a magnetic soliton are experimentally shown in [4]. This is achieved by modifying the ratio of the exchange coupling to the magnetic anisotropy strength of one of the edge layers in a synthetic ferromagnetic superlattice. Here, we further extend this to a system where the magnetic properties of both the edge layers of the synthetic ferrimagnetic superlattice are modified. The magnetic configurations of the superlattice during a hysteresis loop are investigated using macrospin simulation.