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Research was conducted to examine the formation process of cross-hatch patterns (CHPs) and the lattice relaxation process in the growth of an (InAs)1(GaAs)4 strained short-period superlattice (SSPS) and an In0.2Ga0.8As alloy layer on GaAs(100) substrates. It was observed that the lattice relaxation in the (InAs)1(GaAs)4SSPS proceeded as fast as that in the In0.2Ga0.8As alloy layer. A developmental model of CHPs based on the surface diffusion of the In atoms is proposed.

The study of the sputtering power dependence of structural properties of CoCrPt reveals that the sputtering power exerts different types of influences on the characteristics of the sputtered CoCrPt. The study is performed using X-ray diffraction, small angle x-ray scattering and x-ray absorption fine structure studies. The different types of influences occur since the sputtered CoCrPt layers always vary in length.

The relationship between growth processes and strain relaxation in Si1-xGex thin films grown on silicon substrates by gas source molecular beam epitaxy was investigated. The results showed that relaxation of the film strain energy produced a change into faceted structures and occurred at two steps of (811) and (311) faceting with the film growth. The rate constant ratio of the dissociative adsorption of the hydride compounds determined the incorporation ratio of Si and Ge atom into the films.

We fabricated toggle magnetic random access memories with clad writing lines. First, we evaluated the structures and magnetic properties of sputter-deposited cladding layers. The substrate bias during the deposition affected not only the sidewall coverage, but also the crystallinity and magnetic properties of the cladding. The optimized clad lines reduced the writing current to as low as 50% of that of unclad lines. Moreover, the writing current deviation divided by the average current of magnetic tunnel junction cells with clad lines was as low as that with unclad lines. Using the optimized clad lines, we constructed memory arrays with a large operating margin and reduced switching current. Index Terms--Clad line, magnetic property, structure, toggle MRAM, writing current.

Current-driven domain wall motion from pinning sites in nanostrips with perpendicular magnetic anisotropy is analyzed by using micromagnetic simulations, which is supported by a one-dimensional model of wall dynamics. The main features of strips with perpendicular magnetic anisotropy are attractive for magnetic random access memories where the domain wall is moved stably between the pinning sites with the small current pulse.

Current driven domain wall motion in nanostrips with perpendicular magnetic anisotropy is analyzed by using micromagentic simulation. The calculations have shown that the threshold current density of perpendicular magnetic anisotropy (PMA) strips required to depin the domain wall is small although the threshold field is sufficiently large relative to those of in-plane magnetic anisotropy (IMA) strips.

The critical current density needed for the current-induced domain wall motion ([J.sub.c]) is reduced by decreasing the magnetization ([M.sub.s]) of the free layer film of a U-shaped pattern for a domain wall motion memory. It is shown that the decrease in [M.sub.s] has caused a decrease in the hard axis anisotropy of the pattern and the [J.sub.c] has decreased, which is predicted by a one-dimensional model.

The structure and saturation induction ([B.sub.s]) of [Co.sub.90-x][Ni.sub.10][Fe.sub.x] (8 [is less than or equal to] x [is less than or equal] 40) electroplated films have been studied with a view to their use as high-density write-core materials. The [B.sub.s] of the films were slightly larger than those of CoNiFe powders and were increased into the 1.8 to 2.1 T range by controlling the Fe composition and the amount of bcc phase. The latter was achieved by controlling the plating conditions, i.e., the current density and bath temperature. The hyperfine field of the films was about 34 T, slightly larger than that of the powders (33 T), suggesting that their magnetic moments were slightly larger than those of equivalent bulk alloys. The [B.sub.s] values were increased by increases of the amount of bcc phase relative to the equilibrium phase with increasing the magnetic moments. A band calculation showed that the bcc phase had a larger magnetization than the fcc phase although the difference between the total energies of the two phases was fairly small. This confirmed our results. Index Terms--band calculation, electroplating, high [B.sub.s] material, magnetization, Mossbauer effect, soft-magnetic material.