Fe doping effects on the structural, magnetic, and magnetocaloric properties of nano-sized Pr0.6Bi0.4Mn1−x FexO3 (0.1 ≤ x ≤ 0.3) manganites
Résumé
The structural, magnetic, and magentocaloric properties are systematically investigated for Pr0.6Bi0.4Mn1−x Fe x O3 (0.1 ≤ x ≤ 0.3) manganites. The samples have been synthesized by sol–gel method. X-ray diffraction (XRD), scanning electron microscopy, transmission electron microscopy, and Fourier transform infrared spectroscopy were employed to investigate the crystalline structure. Magnetization measurements were used to investigate the magnetic properties. All the samples crystallize in the orthorhombic Pnma space group as expected for manganite compounds. The presence of a PrMn2O5 compound is also evidenced by XRD. The average size of the manganite particles is about 50–60 nm. Particle characterizations at the atomic level turn to be of paramount importance. Magnetic measurements versus temperature under an applied magnetic field of 0.01 T show that all samples exhibit a paramagnetic–ferromagnetic transition. Temperature-dependent magnetization measurements and Arrott analysis reveal second-first order ferromagnetic transitions for (x = 0.1 and x = 0.2). The magnetic entropy change |ΔS M| was estimated using Maxwell relation method and is found to reach maximum values of 0.47 and 0.37 J/kg/K under an applied magnetic field of 5 T for x = 0.1 and x = 0.2, respectively.