Hsini Mohamed

By Mohamed Hsini and Sadok Zemni

In this paper, we have exploited the mean field theory combined with the Bean-Rodbell model to justify the magnetocaloric effect (MCE) in Nd0.67Ba0.33Mn0.98Fe0.02O3 sample. The simulation of some magnetic properties has been investigated. Modeling magnetization curves have been successfully achieved using this model. The second-order ferromagnetic-paramagnetic (FM-PM) phase transition of our system has been verified through the value of the parameter which controls the transition nature in the Bean-Rodbell model. Theoretical and experimental expressions, which have rated the magnetic entropy change ( − ∆ S M ) under various magnetic fields, have been derived. Theoretical ( − ∆ S M ) curves have been compared to the experimental ones.

Part of the book: Magnetometers

By Mohamed Hsini and Souhir Bouzidi

Intermetallic Gd3Ni2 and Gd3CoNi undergo second-order ferromagnetic paramagnetic phase transition at the Curie temperature, TC. They exhibit a large magnetocaloric effect (MCE). This MCE is manifested with a high entropic peak of 8 and 8.3 J.Kg−1 K−1, at the vicinity TC under 5 T magnetic applied field for Gd3Ni2 and Gd3CoNi, respectively. With their boosted MCE and large refrigerant capacity, Gd3Ni2 and Gd3CoNi compounds can be a candidate as a magnetocaloric refrigerator which is still one of the current research projects recommended by the low energy consumption and low environmental impact of these devices. Based on the Landau theory, Gibb’s free energy leads to determine temperature-dependent parameters which correspond to the electron condensation energy and magnetoelastic coupling and the magnetic entropy change which is a very crucial parameter to evaluate the MCE of a given magnetic system.

Part of the book: Latest Research on Energy Recovery