An effect of nitrogen on magnetic properties and microstructure of Fe-Nb-B-N nanocrystalline thin films

Fe-Nb-B-N films with good soft magnetic properties were fabricated by Ar N-2 reactive sputtering. The quaternary films have better soft magnetic pro perties than that of Fe-Nb-B films, The best magnetic properties are satura tion magnetization of 16.5 kG, coercivity of 0.13 Oe and effective permeabi lity of about 5000 up to 10 MHz. It was observed by transmission electron m icroscopy that the Fe-Nb-B-N thin film annealed at 590 degrees C consisted of three phases: a fine alpha-Fe phase whose grain size is around 7 nm, a N b-B rich amorphous phase and NbN precipitates with the size of less than 3 nm. The fine grained alpha-Fe structure, together with finely dispersed NbN precipitates and the amorphous boundary phase are considered to be a main factor for the good magnetic properties. (C) 1998 American Institute of Phy sics.