Magnetic properties of a spin-7/2 and spin-5/2 core/shell nanowire: a Monte Carlo study

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Magnetic properties of a spin‑7/2 and spin‑5/2 core/shell nanowire: a Monte Carlo study N. F. Zounmenou1 · S. I. V. Hontinfinde2 · J. Kple1 · M. Karimou1,3 · F. Hontinfinde1 Received: 4 May 2020 / Accepted: 26 July 2020 © Springer-Verlag GmbH Germany, part of Springer Nature 2020

Abstract We have used Monte Carlo simulations based on the Metropolis algorithm to study the magnetic properties of an Ising nanowire with spin-7/2 core and spin-5/2 shell atoms in the presence of lattice anisotropy and external magnetic field. Only antiferromagnetic interfacial interactions are considered. Thermal variations of the order parameters, phase diagrams, and hysteresis behaviors of the model are calculated. The transitions encountered are of different types: first-order, second-order, compensation, and blocking transitions. It has been found that the magnetic properties of the model, in particular the critical behavior, the compensation, and the hysteresis phenomenon, exhibited are strongly affected by the competition between values of system parameters during the simulations. Keywords  Core–shell Ising nanowire · Monte carlo simulations · Phase diagrams · Hysteresis behaviors · Coercivity

1 Introduction Nanostructured materials have attracted key interest from scientists in the few past decades because of their large number of potential applications in the nanotechnology industry [1–3] and fundamental questions in theoretical research [4, 5]. Ferromagnetic metal nanowires or nanoparticles are special in the field because widely used in various areas such as sensors [6], ultrahigh-density magnetic storage and recording media [7–9], magnetic resonance imaging [10], non-linear optics [11], biomedecine [12], etc. Iron-based nanowires often exhibit novel properties such as magnetoimpedance [13] and nanoscale magnetism [14] due to their special morphology. They have a high reactivity in an air environment, so that they need protection and stabilization through an encapsulating layer leading to a core–shell morphology. It has been shown that through wetting chemical deposition, * F. Hontinfinde [email protected] 1



Département de Physique (FAST) et Institut des Mathématiques et de Sciences Physiques (IMSP), Université d’Abomey-Calavi, 01 BP 613, Porto‑Novo, Benin

2



Ecole Nationale Supérieure de Génie Mathématique et Modélisation (ENSGMM), UNSTIM, Abomey, Benin

3

Ecole Nationale Supérieure de Génie Energétique et Procédés (ENSGEP), UNSTIM, Abomey, Benin



Ag, Au, or Cu shell layers could also be obtained. In these cases of core and shell materials of different nature, combined properties for multifunctional capabilities are expected [15, 16]. Nanowire properties could be tuned by varying the shell thickness to generate a multi-domain state of remanence that is of use in some particular cases for biomedical applications (see Ref. [17] and references therein). The variation of the interfacial magnetic coupling between core and shell materials that can be ferromagnetic or antiferromagnetic, often induces a modification