Post-processing and processing treatment and their effect on structure and properties of Finemet films

The effect of heating of substrates (75°C, 110°C, 145°C and 180°C), electrical bias (50, 75, 100, 125, 150, 200 and 250 V) on the substrate during preparation of amorphous films, and post-annealing on structure and properties of Finemet films were studied. Films were obtained by ion-beam sputtering a Fe73.5Si16.5B6Cu1Nb3 alloy. The structural changes of films due to different annealing temperatures were studied by means of transmission electron microscopy (TEM; Philips CM 300) and X-ray diffraction analyzer (DRON-4). Magnetostatic properties measurements were made with the vibrating sample magnetometer (VSM). Annealing after sputtering decreases the coercive force but its magnitude depends on the preparation conditions. We found that film deposition onto heated substrates had a critical temperature between 110°C and 145°C, at which the film had coercivity Hc>30 Oe. The samples deposited without the bias coercive force decreased after annealing. But the bias voltage during sample preparation reduced this effect of annealing.