Investigation of Mn-Fe magnetic interaction in mechanically alloyed Fe doped-MnAlC by 57Fe Mössbauer spectrometry

Four samples γ2-Mn40Fe0.5Al59.5, β-Mn60Fe0.5Al39.5, and ε-Mn50.5Fe0.5Al47C2, τ-Mn50.5Fe0.5Al47C2 were synthe- sized by mechanical alloying method. X-ray diffraction results showed high purity of the γ2, β, ε, and τ phases in each sample. M ̈ossbauer measurement at room temperature showed non-ferromagnetic characteristic of the γ2- Mn40Fe0.5Al59.5, β-Mn60Fe0.5Al39.5, and ε-Mn50.5Fe0.5Al47C2. Interestingly, τ-Mn50.5Fe0.5Al47C2 showed a complex magnetic hyperfine splitting, indicating magnetic ordered structure. The hyperfine interaction in τ-Mn50.5Fe0.5Al47C2 was found dependent with temperature, in which isomer shift (IS) and magnetic hyperfine field (Bhf) decreased with increasing temperature. From the IS temperature dependence curve, the Debye tem- perature (θD) is determined to be 422 ± 80 K. The temperature dependence of Bhf values and the thermomagnetic measurement yielded a Curie temperature (Tc) values of 560 ± 13 K and 565 ± 2 K respectively. In order to investigate the magnetic interaction between Fe and Mn atoms in τ-Mn50.5Fe0.5Al47C2, local magnetic order of τ-Mn50.5Fe0.5Al47C2 was probed by using in-field 57Fe M ̈ossbauer spectrometry. The obtained results showed that Fe and Mn formed a non-collinear magnetic structure with magnetic moments of Fe at different sites showing different canting angles with neighboring Mn atoms.