Local Structure and Magnetic Properties of FeMnAl Nanocrystalline and Amorphous Alloys

摘要

The structural and the magnetic properties of nanocrystalline and amorphous Fe_(55)Mn_(10)Al_(35) alloys prepared by the mechanical alloying process are studied as functions of the milling time varying from 1 hr to 48 hrs. Structural analyses based on X-ray diffraction (XRD) and extended X-ray absorption fine structure spectroscopy (EXAFS) reveal that the alloying process took place after 12-hr milling. Nanocrystalline alloys are found until 24-hrs milling, and an amorphous phase afterward. Concerning the magnetic behavior, the data obtained from a vibrating sample magnetometer show that both the magnetization saturation (M_s) and the coercivity (H_c) are dependent strongly on the milling time and the crystallite size. By adjusting the milling time, both appropriate structural transformation and magnetization values are obtained.