Magnetic and Magnetocaloric Properties of La0.65Ca0.35MnO3/La0.7Ca0.2Ba0.1MnO3 and La0.65Ca0.35MnO3/Pr0.5Sr0.5MnO3 Composite Manganites

Abstract

La 0.65 Ca 0.35 MnO 3 /La 0.7 Ca 0.2 Ba 0.1 MnO 3 (COMPI) and La 0.65 Ca 0.35 MnO 3 /Pr 0.5 Sr 0.5 MnO 3 (COM-PII) composite manganites were prepared using a conventional ceramic double-sintering process. The microstructural, magnetic and magnetocaloric properties of the composites were investigated using scanning electron microscopy (SEM) and vibrating sample magnetometry (VSM). X-ray diffraction analysis using Rietveld refinement shows that the starting La 0.65 Ca 0.35 MnO 3 , La 0.7 Ca 0.2 Ba 0.1 MnO 3 and Pr 0.5 Sr 0.5 MnO 3 manganites are single phases and crystallize in the orthorhombic system with a Pbnm space group. Magnetization measurements versus temperature for each composite reveal two magnetic transition temperatures associated to both manganites, which induces an enlargement of the magnetic entropy change peak. A better relative cooling power (RCP) value of 308 J kg −1 around 280 K is obtained for COMPI and is W. Cheikhrouhou-Koubaa about 75 % of that observed in pure Gd, which makes our composite a potential candidate for magnetic refrigeration around room temperature.

Magnetic and magnetocaloric properties of 0.5La0.7Ca0.2Sr0.1MnO3/0.5La0.7Te0.3MnO3 composite

“…This result emphasizes that composites have notable advantages for MR applications [34]. Our results obtained in the present work are comparable to several manganites and composites [11,[20][21][22][23][30][31][32] and the results of our and some samples are summarized in Table 1 . Landau theory proposed by Amaral et al [35,36], interpret the contribution of magnetoelastic interaction between electrons on the magnetic entropy change.…”

“…With singlephase systems, to obtain this is not simple and easy. For this reason, composite materials are being formed by using different material groups [20][21][22][23]. In the present work, we have selected La0.7Ca0.2Sr0.1MnO3 and La0.7Te0.3MnO3 manganites.…”