The theoretical study of the magneto-caloric effect in a nano-structure formed on a Dendrimer structure

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The theoretical study of the magneto‑caloric effect in a nano‑structure formed on a Dendrimer structure M. Arejdal1  Received: 2 July 2020 / Accepted: 25 September 2020 © Springer-Verlag GmbH Germany, part of Springer Nature 2020

Abstract The magnetic behaviors and the magneto-caloric effect in a nano-structure formed on a hexagonal Dendrimer structure with the moment spin (S = 7/2) were studied. This examination allowed me, in fact, to observe that the ferromagnetic order appeared above the transition temperature (Tc) whose value was 305 K. Along with this parameter and with the aim of studying other complementary sides of the studied system, other parameters of the system were also calculated; namely, the magnetic entropy change (∆SM), which reached 4.16 J/mol. K, the adiabatic temperature variation (∆Tad), which reached 4.5 K as the maximal value, the relative cooling power (RCP), which had the value of 115 J/mol. It’s worth-noting here that all these results of the MCE were attained under an applied field of 0.6 T and determined by the use of the Monte Carlo method in the calculations done in this research paper. Keywords  Nano-structure · Monte carlo approach · Magnetic properties · Magneto-caloric effect · Magnetic entropy changes · Relative cooling power

1 Introduction Cold occupies a very important place in our daily life. It is used in several areas such as automotive or building air conditioning, industrial or domestic refrigeration, agri-food or medical conservation, etc. Nowadays, the production of cold still relies heavily on conventional compression and expansion techniques such as chlorofluorocarbons (CFCs) and hydrofluorocarbones (HFCs), and hydrochlorofluorocarbons (HCFCs). These, unfortunately, generate greenhouse gases which contribute to the global warming that the world has been experiencing for some years [1–16]. As a solution to this environmental problem, the magnetic refrigeration, using magnetic nanoparticles, is seen as a promising alternative to the conventional compression and expansion techniques thanks to some reasons. First of all, the high efficiency and environmental friendliness of the magnetocaloric effect (MCE) that characterizes the magnetic refrigeration made it a very desirable cooling technology * M. Arejdal [email protected] 1



Laboratory of Condensed Matter and Interdisciplinary Sciences (LaMCScI), Faculty of Sciences, Mohammed V University, B.P. 1014, Av. Ibn Batouta, Rabat, Morocco

[17]. The magnetocaloric effect (MCE) is the variation of a material temperature due to the application or the elimination of an external magnetic field [18]. This temperature change is dependent on the magnetic entropy change (∆SM). As a general rule, the magnetocaloric effect is significant at the transition temperature (TC), where the magnetic spins submit to an order–disorder phase transition. Second of all, the magnetic nanoparticles are very suitable for complex nanotechnology applications because they are easy to be manipulated and distributed in specific geometries [19, 20