Microstructural investigation of RE_3(Fe.V)_(29) (RE = Nd, Tb) magnetic materials

摘要

The microstructure of V stabilized RE_3(Fe,V)_(29) (RE=Nd,Tb) has been investigated by transmission electron microscopy (TEM). The investigated samples were prepared by arc melting and subsequent annealing above 910 deg C. X-ray diffraction confirms that the samples can be indexed based on a monoclinic Nd_3(Fe,Ti)_(29)-type structure (3:29) with A2/m space group. Our TEM investigation confirms that Nd_3(Fe,V)_(29) contains usually grains with 3:29 structure and A 2/m space group. In addition grains with rhombohedral Th_2Zn_(17) structure are observed regularly. The Tb_3(Fe,V)_(29) alloy consists also of grains with monoclinic Nd_3(Fe,Ti)_(29)-type structure and contains a high density of planer defects like crystallographic twins or antiphase boundaries. Twinning occurs preferably on (402) of the monoclinic 3:29 structure. No tetragonal Re(Fe,V)_(12) phase or Fe is found.