Large magnetocaloric entropy change at room temperature in soft ferromagnetic manganites. Issue 1 (20th December 2018)

• Record Type: Journal Article
• Authors: Bouzidi, Souhir; Gdaiem, Mohamed Amara; Dhahri, J.; Hlil, E. K.
• Is Part Of: RSC advances. Volume 9:Issue 1(2019)
• Page Start: 65
• Page End: 76
• Publication Date: 2018-12-20
• Subjects: Chemistry -- Periodicals; 540.5
• DOI: 10.1039/c8ra09166h
• Languages: English
• ISSNs: 2046-2069

Abstract

Abstract : –Δ S M as a function of temperature at different μ 0 H fields, for x = 0.20 compound. The red line curves represent the modeled data and symbols are the experimental data. Abstract : In this paper, La0.75 Ca0.25− x Na x MnO3 ( x = 0.15 and 0.20) samples were prepared by the flux method. Crystallographic study revealed that the x = 0.15 sample is characterized by the coexistence of a mixture of orthorhombic and rhombohedral structures with Pbnm and R 3̄ c space groups, respectively. While, the x = 0.20 sample crystallized in the rhombohedral structure with a R 3̄ c space group. Magnetic data, under a magnetic field of 0.05 T, indicated that our samples undergo a ferromagnetic (FM)–paramagnetic (PM) phase transition, on increasing the temperature. The magnetic field dependence of the magnetocaloric properties of La0.75 Ca0.25− x Na x MnO3 ( x = 0.15 and 0.20) samples, with the second phase transition, was investigated. Near room temperature, the x = 0.20 sample exhibited a large magnetic entropy change with maxima of 6.01 and 3.12 J kg −1 K −1, respectively, under applied magnetic fields of 5 and 2 T. Also, the relative cooling power (RCP) was calculated. According to hysteresis cycles, for our studied samples, at 10 K a typical soft FM behavior with a low coercive field was observed. These results make our samples promising candidates for magnetic refrigerators, magnetic recording, and memory devices.