Surface Dilution Effects on Magnetic Properties and Compensation Phenomena of \({Fe}^{\text{II}}\), \({Fe}^{\text{III}})\) Core–Shell Ferrimagnetic Nanotubes: Monte Carlo Study

Abstract

Using Monte Carlo simulations (MCS), we investigated the magnetic properties and phase diagrams of a hexagonal ferrimagnetic Ising nanotube with a core–shell structure composed of spin-5/2 and spin-2 particles, taking surface dilution into account. Our results revealed several characteristic behaviors. Notably, the concentration of magnetic atoms has a significant influence on both the critical and compensation temperatures. For low values of the exchange interaction \({J}_{s}\)​, dilution has no effect on the critical temperature. However, a compensation point appears beyond a dilution threshold, observed for \(x\ge 0.6\).We also identified critical thresholds for the crystal field anisotropies \({D}_{s}\)​ and \({D}_{c}\)​. Below these thresholds, the critical temperature remains nearly constant, then gradually increases and converges toward a saturation value once the thresholds are exceeded. Furthermore, the analysis of hysteresis loops shows that the system’s magnetic response is highly influenced by dilution: the remanent magnetization increases significantly in absolute value as the concentration of magnetic atoms rises from \(0.6\) to\(1.0\).