Study of magnetization in amorphous Fe73.5Cu1N3Si13.5B9 and Fe73.5Si1P3C13.5Cr9 alloys

We studied metallic systems, showing a great technological interest, like Fe73.5Cu1N3Si13.5B9 and Fe73.5Si1P3C13.5Cr9 alloys prepared by the melt spinning method. We performed some magnetic measurements ( M (T) and M (H)) on these samples and we introduced theoretical models to determine the origins of their magnetic properties concerning exchange and anisotropy. Then using the spin wave theory we determined the exchange stiffness constant D which is about 82.6 meV Angstrom(2) and 88.8 meV Angstrom(2), respectively, for Fe73.5Cu1N3Si13.5B9 and Fe73.5Si1P3C13.5Cr9. From the D values we deduced the interatomic distance r(Fe-Fe) which is equal to 2.5 Angstrom. Applying Chudnovsky's model to these samples we determined some fundamental parameters such as exchange (Hex) and random anisotropy (Hr) fields and the random local anisotropy constant K. These results show that our samples have the behaviour of a weak local random anisotropy magnetic system (Hr much less than Hex).