[en] The properties of Co/CoO_x exchange-coupled spin valves are explored at temperatures to 5 K. The spin valve structure is: 100 A CoO_x/30 A Co/30 A Cu/10 A Co/50 A NiFe/50 A Ti. Our discovery is the considerable differences between the properties of the spin valves for which the CoO_x layer is prepared in different O₂ concentrations

[en] The site is a 72,846 square meter (18-acre) abandoned strip mine located in Western Pennsylvania used for municipal and industrial waste disposal until the mid-1970's. The waste pit is adjacent and connected to a flooded deep mine which saturated the waste over the past 20 years. The site was placed on the National Priority List in 1984, primarily due to the presence of drums on the surface of the site. EPA's proposed remedial action for the site included excavation and stockpiling of the waste materials, backfilling the pit with clean materials, constructing a RCRA cell on the clean materials, and disposing of the waste into the cell. The estimated cost of EPA's remedy was approximately $26 million. An alternative action proposed included in-place closure and containment at the site. Many were unsure whether a slurry cutoff wall could be installed through the deep mine adjacent to the waste pit. The proposed alternative of grouting mine voids to facilitate slurry wall installation had never been performed on a Superfund site, and resulted in a cost savings of approximately $15 million. The grout and slurry wall were successfully installed, with complete closure expected by spring of 1997

[en] Shallow Soil Mixing (SSM) and Soil Vacuum Extraction (SVE) are techniques which have been increasingly relied on for the insitu remediation of contaminated soils. The primary applications of SSM have been to mix cement, bentonite, or other reagents to modify properties and thereby remediate contaminated soils or sludges. Soil vacuum extraction has been used at numerous applications for insitu removal of contaminants from soils. At a recent project in southern Ohio, the two technologies were integrated and enhanced to extract volatile organic compounds (VOCs) from soils at a Department of Energy facility. Advantages of the integrated SSM/SVE technology over alternative technologies include a relatively rapid remediation compared to other in-situ techniques at a lower cost, less exposure of waste to the surface environment and elimination of off-site disposal. These advantages led to the selection of the use of both technologies on the project in Southern Ohio. The information presented in this paper is intended to provide Engineers and owners with the level of understanding necessary to apply soil mixing and vacuum extraction technology to a specific site. The most important steps in implementing the technology are site investigation, feasibility estimate, selection of performance criteria, selection of appropriate materials, bench scale testing and construction

[en] Cobalt ferrite, CoFe₂O₄, thin films are explored as pinning layers for read sensor applications. High ΔR/R values, 12.8%, and high pinning fields, 1500 Oe, are observed. Unlike other coercivity based pinning layers, the soft properties of the free layer are not compromised. The properties of the cobalt ferrite layers are strongly dependent on the microstructure, which, in turn, depends on the reactive sputtering process

[en] Epitaxial CoO-NiO multilayers have been produced which show interesting structural and magnetic properties. The single Neel temperature observed for left-angle 111 right-angle oxide multilayers grown on α-Al₂O₃ together with similar results found for FeF₂-CoF₂ multilayers, suggest that the magnetic properties of different ionic antiferromagnets can be mixed through alloying. This prompted the current study to produce Ni_xCo_1-xO thin films in order to study their magnetic properties. The structure of these films is discussed in this paper. Epitaxial films of NiO and CoO have been produced on α-Al₂O₃ by some of the authors and others. High quality left-angle 111 right-angle films were produced by reactive sputtering and reactive evaporation confirming the epitaxial growth of the cubic monoxides on the rhombohedral (hexagonal) α-Al₂O₃. However, it was found that the monoxide films consisted of columnar grains epitaxial with the substrate, but adjacent grains related by a 60 degrees rotation twin relationship. The exact cause of the twinning was unclear. In this respect, the twinning is found to result from the order which left-angle 111 right-angle planes of the cubic monoxide stack on the surface of the hexagonal α-Al₂O₃. Typically, epitaxial films are grown either by chemical vapor deposition or evaporation. However, sputtering can also yield high quality epitaxial layers, often at reduced substrate temperatures. Reductions in substrate temperature can be advantageous. NiO-CoO solid solutions have been shown to phase segregate at high temperatures. Also, reactions at the film-substrate interface are undesirable. Thus, sputter deposition was chosen for the production of the films discussed in this research

[en] We report a phase instability in oxygen-plasma-assisted molecular beam epitaxy of Fe₃O₄ films on sapphire (0001) substrates. Under a wide range of growth conditions, Fe₃O₄(111) films phase separate, on a nanometer length scale, into Fe₃O₄, FeO and metallic Fe, which is attributed to formation of the thermodynamically unstable phase FeO in the initial stages of (111) growth. In contrast, Fe₃O₄(001) films, grown simultaneously on MgO(001) substrates, do not exhibit this phase instability. We specify growth conditions for which single-phase, epitaxial Fe₃O₄(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 Fe₃O₄(111) films are much more difficult to magnetize than Fe₃O₄(001) films and phase separation makes the films even more difficult to magnetize

[en] Quantitative x-ray diffraction (XRD) and high resolution electron microscopy (HREM) have been applied to the analysis of an epitaxial CoO/NiO superlattice. This example shows that the qualitative information determined directly from a XRD spectrum or HREM image is limited and can even be misleading. However, by a combination of quantitative intensity measurements and structural modeling, a detailed quantitative characterization of the superlattice structure is possible