The magnetic properties and microstructures of Fe-Cr-Co thin films obtained by ion beam sputtering

Fe-Cr-Co ternary alloy films were obtained by ion beam sputtering. According to their chemical composition, the specimens can be classified into two groups: (1) Fe-XCr-Co (X = 28, 40, 50, 60, 70 wt.%), W-Fe/W-Co = 1; (2) Fe-28Cr-XCo (X = 15, 25, 36, 45, 56 wt.%). After sputtering, the films were heal-treated at temperatures within the miscibility gap. After annealing, the separated phases and lattice images were determined by high resolution analytical electron microscope. With an increase in the Cr content, both the M(s) and M(r) values decrease while H-c tends to increase. For the Fe-XCr-Co alloys, a typical H-c value of 783 Oe for the Fe-60Cr-20Co film was obtained after aging at 550 degrees C for 80 min. However, the Fe-Cr-XCo alloys have higher M(s), M(r) values, loop squareness and smaller H-c values compared with Fe-XCr-Co alloys. The maximum M(s), M(r) values and loop squareness for the Fe-28Cr-15Co alloy are 1555 emu cm(-3), 1265 emu cm(-3) and 0.813 respectively. Raising the Co content can increase H-c. As a whole, the heat-treatment time for the Fe-Cr-Co thin films is much less than that of bulk materials.