SOFT-MAGNETIC PROPERTIES OF NANOCRYSTALLINE FE-M-(B AND OR O) (M=GROUP IV-A, V-A ELEMENTS) ALLOY-FILMS/

In Fe-M-(B and/or O)(M= group IV A, V A elements) alloy films, nanocry stalline bcc phase are formed by annealing the amorphous single phase for Fe-M-B films, whereas the bcc nanocrystals are already formed in a n as-deposited state for Fe-M-O or Fe-M-B-O) films. Among Fe-M-B films with various M elements, Fe-(Zr, Hf,Nb, Ta)-B alloy films exhibit hig h saturation magnetization (Is) above 1.4 T and high relative permeabi lity (\ mu \) above 1000 at 1MHz. The highest \ mu \ of 3460 at 1MHz i s obtained for Fe78.5Nb8.3B13.2 alloy film. On the other hand, Fe-(Hf, Zr)-O alloy films exhibit the flat frequency characteristics of mu' o f approx. 1000 up to 100MHz owing to their considerably higher electri cal resistivity (rho) than that of Fe-M-B alloy films. Both the films consist of fine-grained bcc phase with diameter below 20 nm and an amo rphous phase containing larger amount of M elements than that in the b cc phase. In Fe-Hf-B-O alloy films, the rho values as high as the Fe-H f-O alloy films are obtained in higher Fe content than the Fe-Hf-O fil ms. As a result, Fe68.9Hf10.2B1.0O19.9 film simultaneously exhibits th e higher Is of 1.4T, higher mu' of 1310 at 100MHz, and lower saturatio n magnetostriction (lambda s) of 2.2 x 10(-6) than those of Fe54.9Hf1. 10O34.3 alloy film.