Magnetic Phase Transitions and Hysteresis in Hexagonal Multi-layered Core/Double-Shell Nanowires

Abstract

We investigated the magnetic properties and phase transitions of a hexagonal Ising multi-layered core/double-shell nanowire comprising a spin-5/2 core, a spin-1 inner shell, and a spin-3/2 outer shell. Using Monte Carlo simulations based on the Metropolis algorithm and exact calculations of ground-state phase diagrams, we explored the system’s behavior under various Hamiltonian parameters. The zero-temperature ground-state diagrams (GSDs) revealed multiple stable configurations with diverse topologies, including a compensation phenomenon for negative crystalline fields (\(\Delta \)). The phase diagram in the (T, \(\Delta \)) plane was mapped, identifying ferromagnetic, semi-ordered, and paramagnetic phases. The temperature dependence of total and partial magnetization was analyzed for different values of \(\Delta \), external field (h), and interface exchange couplings (J\( _{int}\)). Additionally, hysteresis loops were studied under varying nanowire length (L), temperature (T), and J\(_{int}\), revealing a strong correlation between these parameters and the loops’ shape. This study provides significant insights for the design and optimization of next-generation nanomagnetic systems, with potential applications including, advanced memory storage devices and spintronic components.