Magnetic performance of amorphous manganese nanoparticles doped with rare earth elements

Abstract

We studied magnetic and magnetocaloric response in nanoparticle manganite oxides (ABO3-type manganese oxides), which were chemically prepared by sol–gel method with different composition RMnO3 (R = Gd, Tb, Ce) (GMO, TMO, CMO). The structural characterization was performed by EDX (Energy-dispersive X-ray spectroscopy) technique, using TEM (Transmission electron microscopy) methods and XRD and confirmed the nanosized character and morphology of studied manganites. Despite the amorphous character of the samples RMnO3 (R = Gd, Tb), the relatively large magnetic entropy change − ΔSM(7 K) ∼15 J/kgK and − ΔSM (13 K) ∼8 J/kgK has been observed in the case of GMO and TMO, respectively. Sample CMO, despite of its crystalline character, exhibits the lowest magnetic entropy change and the magnetic properties are affected by Jahn-Teller distortion in Mn3O4 nanoparticles (NPs). All systems GMO, TMO, CMO exhibit the Arrott plots with linear behavior and positive slopes that is according to the Banerjee criterion a signature of the second order phase transition. This is in line with our conclusions on the presence of AFM-PM phase transitions in the systems that we drew from ZFC-FC data. Our results confirm that also amorphous manganites especially with Gd show feasible properties for potential magnetic refrigeration applications.