Ferromagnetic Resonance of HE3-Irradiated Thin Metal Films

摘要

Ferromagnetic-resonance measurements at 9.5 GHz were made on a number of films of pure iron and pure nickel, and alloys of iron and nickel (Permalloy) before and after 2-MeV He3-particle irradiation. In general, H0 decreased (by about 2 oe, 35 oe, and 15 oe for the iron, Permalloy, and nickel films, respectively) as a result of the irradiation, except for the composition range between 26 and 37 percent Ni, where H0 increased. Also, the half-width generally decreased with irradiation. For the pure iron and nickel films, the changes in H0 can be attributed to changes in the radially isotropic stress in the plane of the film, and in the uniaxial anisotropic field. For the alloy films where irradiation-produced ordering may occur, Ms, as well as the above parameters, may also change. The changes in H0 were different for films of a given set evaporated onto various substrates (soft glass, fused quartz, single-crystal quartz, and copper). Irradiating a film (or reirradiating a previously irradiated film) in a magnetic field also rotated the easy axis of the film into the direction of the field applied during irradiation. The rotation of the easy axis was observed over the entire composition range from pure iron to pure nickel. For the pure iron and pure nickel films, the rotation can be explained only on the basis of alignment of defects in the film during irradiation. For the Permalloy films, a short-range directional ordering effect might also apply. The variation with composition of the values of uniaxial anisotropic field after irradiation agree qualitatively with the values obtained by others using static techniques. (Author)