Comparison of amorphous and crystalline FeB

Abstract

We have studied amorphous FeB made by high-rate sputtering. The results are compared with those of crystalline FeB containing a single Fe site. The quadrupole splittings and the isomer shifts measured in the paramagnetic state and the hyperfine-field distribution measured in the ferromagnetic state show considerable differences between amorphous and crystalline FeB. These results indicate dissimilar short-range order in the amorphous and crystalline states. The hyperfine field of amorphous FeB decreases more rapidly with temperature than that of crystalline FeB. This clearly illustrates the effects of a distribution of exchange interactions in an amorphous ferromagnet as opposed to a single-site crystalline ferromagnet.