Synthesis of Fea€“Sia€“Ba€“Mn-based nanocrystalline magnetic alloys with large coercivity by high energy ball milling

摘要

Alloys of Fea€“Sia€“B with varying compositions of Mn were prepared using high energy planetary ball mill for maximum duration of 120 h. X-ray diffraction (XRD) analysis suggests that Si gets mostly dissolved into Fe after 80 h of milling for all compositions. The residual Si was found to form an intermetallic Fe₃Si. The dissolution was further confirmed from the field emission scanning electron microscopy/energy dispersive X-ray analysis (FE-SEM/EDX). With increased milling time, the lattice parameter and lattice strain are found to increase. However, the crystallite size decreases from micrometer (75a€“95 e???m) to nanometer (10a€“20 nm). M??ssbauer spectra analysis suggests the presence of essentially ferromagnetic phases with small percentage of super paramagnetic phase in the system. The saturation magnetization (e?‘€_s), remanance (e?‘€_r) and coercivity (e???_c) values for Fea€“0Mn sample after 120 h of milling were 96.4 Am2/kg, 11.5 Am2/kg and 12.42 k Am-1, respectively. However, for Fea€“10Mna€“5Cu sample the e?‘€_s, e???_c and e?‘€_r values were found to be 101.9 Am2/kg, 10.98 kA/m and 12.4 Am2/kg, respectively. The higher value of magnetization could be attributed to the favourable coupling between Mn and Cu.