Diffractometric investigation of the modulated structure in Alnico-type permanent magnets

Samples of Ti-containing Alnico alloy in the high coercive state were subjected to an X-ray diffractometric investigations. Two surfaces of the samples were investigated: one parallel and the second perpendicular to the lines of the forces of the external magnetic field H. The investigations showed that the alloy had the structure of an ordered solid solution with cubic body centered lattice where ((a)=0.2873+or-0.0003 nm). There is a superstructure of the CsCl type. There is a periodic modulation of the interplanar spacing and scattering power in the direction perpendicular to the force lines of the external magnetic field H. It is supposed that this periodic modulation is caused by a periodic variation of the composition-there is a higher concentration of Al-atoms in the region where a1>(a) and a higher concentration of Fe-atoms in the region, where a2<(a). These regions in TEM investigations are identified with two separate phases alpha ₁ and alpha ₂.