Tunable static magnetic susceptibility in multicore particles via nanocore number and arrangement

Abstract The magnetic response of multicore magnetic particles (MCMPs) is governed by a complex interplay of factors including the number of magnetic cores (grains), their packing density, their spatial arrangement and the intergrain magnetic interactions. Using Monte Carlo simulations, we investigate a model system where magnetic grains are arranged in a simple cubic lattice, revealing a fundamental relationship between the MCMP static magnetic susceptibility and the orientational ordering of the grains’ magnetic moments induced by dipole–dipole interactions. Our results demonstrate that the number of grains critically determines the magnetic response: MCMPs with an even number of grains predominantly form closed-loop magnetic moment structures, leading to reduced magnetisation, whereas MCMPs with an odd number of grains can exhibit locally orthogonal magnetic configurations, resulting in significantly enhanced susceptibility. This finding reveals that even minor changes in grain number can cause substantial variations in magnetic response highlighting the importance of structural control in material design.Also we establish that small MCMPs offer the greatest potential for magnetic property control, as their susceptibility shows strong dependence on internal structural modifications. By precisely designing MCMP structures, it becomes possible to optimise their magnetic properties for advanced medical technologies, particularly in the development of magnetic markers for biological cell tracking and targeted drug delivery systems.