Magnetic damping in Fe-based films deposited by laser ablation in magnetic field

Magnetic films were deposited on oxidized Si by KrF laser ablation of amorphous ribbons (composition Fe60Ni20B20, Fe64 xNbxCo21B15 with x = 0–5 and Fe73.5 xNixCu1Nb3Si13.5B9 with x = 0–40). The deposited films are amorphous. Deviation from stoichiometry is low. The magnetization motion damping parameter l and magnetization of the films were obtained from ferromagnetic resonance (FMR) spectra at 18, 25, 49 and 70 GHz. The lowest l value obtained is 5.1 107 rad/s for a Fe33.5Ni40Nb3Cu1Si13.5B9 film. Here, the magnetization was only 7.99 kG because of low content of Fe. But high magnetization around 16 kG, combined with acceptable damping parameter (l = 9.1– 9.8 107 rad/s), was measured in Fe60Ni20B20 films. For the samples deposited in the external magnetic field of 30 mT parallel to the substrate surface an in plane uniaxial anisotropy is observed, which is 5 10 3 erg/cm3 in the film with the lowest damping parameter. The Fe-rich film Fe73.5Nb3Cu1Si13.5B9 shows a much higher anisotropy of 17.9 10 3 erg/cm3. Such combinations of properties are appropriate for the application of this kind of films in fast magnetic devices