STRUCTURE AND SOFT-MAGNETIC PROPERTIES OF FEAL FEN MULTILAYERED FILMSWITH HIGH B-S AND MU/

The structural and soft magnetic properties of FeAl/FeN multilayer fil ms with high spontaneous induction B-s and permeability mu are investi gated. The thickness of the FeAl layer is fixed at about 675 Angstrom, while that of the FeN layers is varied from 135 to 675 Angstrom. For the larger thicknesses of FeN layer the X-ray diffraction patterns con tain peaks from gamma'-Fe4N and alpha-Fe. The peaks become narrower wh en the FeN layers become thicker. Atomic force microscopy reveals that the grain size is smaller for films with thinner layers of FeN. B-s i s high (> 16 kG) and almost independent of the thickness of the FeN la yer. The coercivity H-c decreases and mu increases when the FeN layer becomes thinner. When the thickness of the FeN layer is 135 Angstrom, the coercivity is low (about 1 Oe), mu is high (2000 at 13 MHz), and m u changes little from 1 to 13 MHz. These results can he understood qua litatively on the basis of an increase of mu caused by enhanced cohere nt rotation in small particles.