Magnetic state of Mn in Fe/sub 40-//sub x/Ni40Mn/sub x/B12Si8 before and after crystallization

We have prepared amorphous Fe/sub 40-//sub x/Ni40Mn/sub x/ B12Si8 ribbons by melt spinning and investigated them using magnetometry and spin echo spectrometry. The magnetization increases with the addition of Mn, by 17% for x = 0.5. Such an increase is not observed for Ni concentration in less than 40. The NMR frequency of 55Mn at 4 K for x = 0.5 is 380 MHz (μ/sub Mn/ = 3.3μ/sub B/) and it decreases to 340 MHz for x = 5.5. The Mn moments are found to be aligned ferromagnetically to that of the alloy. The presence of Mn also leads to an increase in the magnetic moment of Fe+Ni. After crystallization, one observes in the alloy with x = 5.5, two 55Mn impurities in two different compounds. The former should be a canted antiferromagnet and the latter a normal ferromagnet. The temperature-dependence results are also discussed