Magnetic and magnetocaloric properties of nano-sized La0.8Ca0.2Mn1−x Fe x O3 manganites prepared by sol–gel method

Abstract

We present an investigation on magnetic and magnetocaloric properties of nano-sized La0.8Ca0.2Mn1−x Fe x O3 (x = 0, 0.01, 0.15, 0.2) manganites synthesized by sol–gel process. X-ray diffraction and magnetization measurements were performed to investigate both crystallographic structure and magnetocaloric properties, respectively. All samples show an orthorhombic structure with Pnma space group. Ferromagnetic–paramagnetic transition sensitive to iron doping is observed at Curie temperature (T C) ranging from 223 K (x = 0) to 70 K (x = 0.2). In addition, a large magnetocaloric effect near T C is observed. Under a magnetic field change of 5 T, a maximum of magnetic entropy $$\Delta S_{\text{M}}^{ \hbox{max} }$$ reaches 4.42, 4.32, 1.6, and 0.54 J kg−1 K−1, for x = 0, x = 0.01, x = 0.15, and x = 0.2, respectively. The relative cooling power (RCP) values were computed as well. RCP values of 164 and 117 J kg−1 were found for La0.8Ca0.2MnO3 (LCM) and La0.8Ca0.2Mn.0.99Fe0.01O3 (LCMFe0.01), respectively. The large values of entropy changes and related RCP allow concluding that our material could be a highly attractive candidate for magnetic refrigeration.