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The critical damping constant of the magnetization of a uniformly magnetized ferromagnetic ellipsoid can be expressed by a simple formula based upon the small signal solution of the Landan--Lifshitz--Gilbert equation. It is predicted from the damping criteria that the damping condition of the magnetization in a uniformly magnetized ferromagnetic ellipsoid can be controlled by adjusting the damping constant, shape, anisotropy field, and/or external magnetic bias field, which is confirmed experimentally in thin-film geometry. Index Terms--Damping constant, damping criteria, ferromagnetic resonance, Landau-Lifshitz, soft magnetic films.

Magnetization dynamics measurements at subnanosecond time scale have been performed on Fe-Co-N high-saturation soft magnetic films with Permalloy nanolayer seeds and having a saturation magnetization of 1.9 MA/m (1900 emu/[cm.sup.3]). The damping parameter [alpha] varies from 0.011 to 0.018, depending on applied bias field. The peak frequencies of the imaginary permeability spectra and the zero-crossing frequencies of the real permeability spectra cannot be fitted with a fixed value of anisotropy field, indicating that the Kittel equation is only qualitatively valid for these films. A phenomenological damping criterion is established based on a small-signal solution of the Landau-Lifshitz-Gilbert equation: critical damping occurs in a soft magnetic film when the damping parameter is [alpha] -- 2/[square root of [[chi].sub.0]], where [[chi].sub.0] is the initial permeability. The experimentally observed damping parameters are smaller than the critical value for the range of bias fields employed. The Fe-Co-N-based films have a ferromagnetic resonance frequency of 2 GHz at zero-bias field, showing great promise for applications in write heads and integrated inductors in a frequency range > 1 GHz. Index Terms--damping parameter, Fe-Co-N film, ferromagnetic resonance, Landau-Lifshitz-Gilbert equation, magnetic thin film.

Intra-pattern and Inter-pattern demagnetization fields cause the appearance of NonLinear Transition Shift (NLTS) and Hard Transition Shift (HTS). Additional timing shifts at high frequency writing reinforce both intra-pattern and inter-pattern non-linearities. A model describing interaction of the timing and the density transition shifts for a dibit transition is proposed. Experimental results indicate strong interaction between adjacent transition in series and significant oscillations of transition shift.

NiO exchange-biased 'bottom' spin valves of the type NiO/NiFe/Co/Cu/Co/NiFe and FeMn exchange-biased 'top' spin valves of the type NiFe/Co/Cu/Co/NiFe/FeMn were deposited by ion-beam deposition (except the NiO layer). Their magnetic properties, magneto-transport, and microstructures are characterized and compared with corresponding GMR spin valves deposited by dc magnetron sputtering. High-resolution cross-sectional transmission electron microscopy and X-ray diffraction reveal microstructural differences between ion-beam-deposited and dc magnetron sputtered spin valves. In particular, film texture, surface morphology, GMR ratio, exchange bias, interlayer coupling strength, and coercivity vary widely, but property-structure-processing correlation can be identified. A GMR ratio of [approximately]9.7 % was obtained on random textured NiO exchange-biased bottom spin valves by ion-beam deposition. Index Terms - Ion-beam applications, magnetic recording/reading heads, magnetoresistive materials/devices.