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We report a phase instability in oxygen-plasma-assisted molecular beam epitaxy of Fe[sub 3]O[sub 4] films on sapphire (0001) substrates. Under a wide range of growth conditions, Fe[sub 3]O[sub 4](111) films phase separate, on a nanometer length scale, into Fe[sub 3]O[sub 4], FeO and metallic Fe, which is attributed to formation of the thermodynamically unstable phase FeO in the initial stages of (111) growth. In contrast, Fe[sub 3]O[sub 4](001) films, grown simultaneously on MgO(001) substrates, do not exhibit this phase instability. We specify growth conditions for which single-phase, epitaxial Fe[sub 3]O[sub 4](111) films can be grown by plasma-assisted molecular beam epitaxy or by reactive evaporation of Fe in molecular oxygen. Film orientation and phase separation strongly influence magnetic properties. Single-phase Fe[sub 3]O[sub 4](111) films are much more difficult to magnetize than Fe[sub 3]O[sub 4](001) films and phase separation makes the films even more difficult to magnetize. © 2003 American Institute of Physics. [ABSTRACT FROM AUTHOR]

Describes the structural and magnetic properties of [111]-oriented multilayers comprising ferromagnetic films of Permalloy-silver alternating with silver spacer films. Experimental techniques; Film growth; Magnetoresistance results; Conclusions.

Investigate the magnetic microstructure of thin epitaxial FexPt1-x ordered alloy thin films using off-axis electron holography at the nanometer level. Defective areas associated with local perturbations of the in-plane magnetic field; Variations in phase shifts in the vacuum.

The role of magnetic, structural, and chemical roughness on the origin of exchange biasing in polycrystalline Mn[sub 52]Ni[sub 48]/Fe[sub 92](Mo[sub 8]) bilayers has been investigated by transmission x-ray magnetic circular dichroism (XMCD), vibrating sample magnetometry (VSM), and transmission electron microscopy (TEM). Three bilayer samples of MnNi(22 nm)/Fe(Mo) (6 nm) were grown by molecular beam epitaxy under ultrahigh vacuum conditions with the MnNi layer at temperatures of 200 °C, 250 °C, and 300 °C. The exchange bias, H[sub e] was observed to be the largest for the 250 °C growth sample. The angular dependence of H[sub e] can be well modeled in terms of a cosine series with odd terms confirming the unidirectional nature of the anisotropy energy. However, the coefficients are different for the three samples indicating different microscopic magnetic interactions at the interface. XMCD measurements showed no magnetic moment for Mn and Ni but showed systematic variations of the Fe moment, i.e., a decrease in Fe moment with increase in H[sub e] was observed. We have interpreted this decrease in Fe moment in terms of antiferromagnetic (AF) ordering of Fe at the interface with the extent of the AF ordering being related to the magnitude of the exchange. Thus, for samples grown at 250 °C, it is found that at least about 4 MLs of Fe appear to be AF. Preliminary energy-filtered imaging of cross-section samples shows that the Fe layer is chemically rough suggesting that the decrease in moment may arise from the intermixing of Fe with the MnNi layer. © 2000 American Institute of Physics. [ABSTRACT FROM AUTHOR]

The magnetotransport and magnetic properties of chemically ordered (001) L1[sub 0] FePt epitaxial thin films with small scale perpendicularly magnetized stripe domains have been investigated. Film growth conditions are used to systematically vary the degree of chemical order, the magnetic anisotropy, and magnetic domain sizes. The longitudinal and transverse (Hall) resistivities are correlated with both film chemical order and magnetic properties. The low-field magnetoresistance shows evidence of domain effects. In the highest anisotropy and most chemically ordered film studied, this low field magnetoresistance is consistent with an intrinsic domain wall scattering contribution to the resistivity. © 2000 American Institute of Physics. [ABSTRACT FROM AUTHOR]

Presents a study that grew high-purity galliumarsenic (GaAs) on A[sub1] and B orientations by molecular-beam epitaxy. Type of growth in undoped GaAs; Liquid-nitrogen electron mobility of B orientation; Results of the low-temperature photoluminescence.

Describes the growth of epitaxial films of the L1[sub0] phase of iron platinum (FePt). Compositions, long-range order parameters and mosaic spread for FePt films; Ways in which FePt films were prepared; Magnetization loops for FePt films.

Presents a study which investigated the microstructure and magnetic properties of phase-separated iron-silver and cobalt-silver granular alloy films, grown epitaxially on (001) sodium chloride substrates and exhibiting giant magnetoresistance. Experimental procedures; Results; Conclusions.

Presents full-profile structural modeling of both low- and high-angle X-ray diffraction scans. Formalism that describes the specular reflectivity of X-rays; Description of the crystalline order; Consequence of the inherent sensitivities of the measurements.

Presents a study which examined the molecular beam epitaxy growth of cobalt/platinum superlattices on epitaxial silver films on gallium arsenide substrates. Experimental details; Superlattice growth and structure; Conclusion.