Structural, magnetic and Mössbauer studies of Ndfe_xmn_1-Xo₃ perovskite Manganites

The influence of Fe-doping on the structural and magnetic properties of NdFe_xMn_1-xO₃ (x = 0.1, 0.3, 0.5, 0.7, 0.9 and 1.0) nanoparticles was investigated. Auto-combustion sol-gel technique was used to synthesize the compounds. X-Ray diffraction refinement indicated that all samples were formed a single-phased orthorhombic structure with Pbnm space group. The M-T curves measurements at an applied magnetic field of 0.2 T demonstrated that all compounds undergo antiferromagnetic (AFM) to paramagnetic (PM) transition as the temperature increased in which the Nèel temperature was observed below ⁓10 K for all compounds except for NdFe_0.3Mn_0.7O₃ compound (62 K). ⁵⁷Fe transmission Mӧssbauer spectra were measured at room temperature (295 K) and liquid nitrogen temperature (78 K) for all compounds. The magnetic ordering of these compounds was highly dependent on iron content. The compounds with low iron concentration at 295 K and at 78 K were characterized by a dominant paramagnetic high-spin Fe³⁺ doublet. The hyperfine magnetic field distribution was responsible for the broadening of the magnetic sextet of the room temperature Mӧssbauer spectrum with x = 0.7. The ⁵⁷Fe Mӧssbauer spectra with higher iron doping at both 295 K and 78 K demonstrated well resolved magnetic sextet with a hyperfine magnetic field increased linearly with increasing x.