Magnetic Properties and Microstructures of Nanocrystalline Fe-M(M=Y, Ce)-O Films

Recently, Fe-based nanocrystalline soft magnetic alloys with high saturation magnetization (Bs) produced by melt-spinning and sputtering have been discovered. Most of these alloys are obtained by annealing amorphous phase, adding and consequently there is a limit to the Bs obtained by glass-forming elements. We have been studying soft magnetic alloy films with high Bs, which have nanocrystalline structures in an as-deposited state. In this paper, we describe the magnetic and structural properties of nanocrystalline Fe-M-O(M=Y, Ce) alloy films. Y or Ce and O elements in the films have a tendency to make the bcc grains finer in an as-deposited state, and also repress the growth of the grains in an annealed state caused by the existence of very fine oxide particles, less than 10 nm in size, containing Y or Ce. The highest Bs, μe at 1 MHz, and the lowest Hc values reach 1.95 T, 1200 and 0.6 Oe for a Fe85Y4O11 film annealed at 773 K for 3.6 ks.