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Research shows that thin films of Fe(sub)3O(sub)4 can be deposited on gold single-crystal substrate by aniodic electrodeposition at 90 C using a Fe(II) ionic solution. Data show differences in the orientations of the epitaxial thin film deposition are due to differences in the gold species used.

Electrodeposited microtubes were investigated to determine closure domain penetration, using magnetic force microscopy and giant magneto-impedance methods.

Issues concerning the preparation of Ag tapes using electrodeposition are discussed. The method includes the Co-deposition of T1(1212) and T1(1223) and high temperature heat treatment to form the superconducting phase. Advantages of the method including cost and speed are detailed.

Iron particles of nanometer-size were grown in a silica gel using the electrodeposition technique.

The use of diffuse reflection spectroscopy to measure the optical properties of the powders of cadmium selenide nanoparticles is described. The powders were prepared by a pulsed sonoelectrochemical technique and crystal size varied from x-ray amorphous to 9 nm.

The zinc electrodeposition in highly concentrated KOH solutions at low mass transport rates induced by a magnetic field was investigated using the EIS method. Two diffusion coefficients, Zn(II) and OH-, were found to govern the reaction mechanism despite considering only the cathode current contribution. Moreover, the charge transfer kinetics were not affected by magnetic fields that are less than 1 T.

A study was conducted to examine the electrodeposition of patterned magnetic nanostructure devices supporting submicronic dimensions using the template technique. The faces of a doped silicon substrate were metallized by sputtering gold on chromium before pure multilayers were electrodeposited into the cavities. Experimental results indicated that the template method can effectively fabricate magnetic metallic nanostructures.

Ultrapure preparation conditions equivalent to ultrahigh vacuum conditions of 5 x [10.sup.-10] mbar allow the reproducible deposition of magnetic films in the monolayer (ML) range from aqueous electrolytic solutions. We used this cost and time efficient technique to prepare ultrathin Co films on Cu(001) substrates. A unique feature of electrodeposition is its ability to dissolve previously deposited layers. The thickness of deposited films can be adjusted in situ by dissolution without damaging the rest of the film. This might be useful in precisely tailoring film properties, for example in magnetic multilayers. In situ magneto-optical Kerr effect (MOKE) measurements are a simple and efficient tool for such a purpose and provide a thickness resolution of better than 0.2 ML. The magnetic properties and anisotropies of the electrodeposited films as derived from our in situ MOKE measurements are mainly determined by their epitaxial growth on Cu(001). Index terms - Co, electrodeposition, magnetic thin films, ultrathin films

Optical constant tests on electrodeposited films of cadmium telluride (CdTe) taken from opaque substrates and shifted to glass slides showed an optical dispersion identical to that of a single crystal CdTe. Perfect matches were also obtained for optical absorption coefficient of films and single crystals across various photon energy levels. However, a maximum of only three identical optical transitions were observed for E greater than 3.5 eV.

Electrolytic deposition of sulphur-carrying thin organic dioctadecyldithiocarbonate (DODTC) films forms a new method for the passivation of GaAs surface for metal-insulator-semiconductor applications. DODTC films have long alkyl chains which are extended and function as insulators. The DOTC has a reduced depletion layer width and exhibits a depining when used in combination with GaAs.

Polycrystalline GaAs films are synthesized using economical, simple and environment-friendly electrodeposition technique. Enhanced technological parameters produce high quality films. Electrodeposition of polycrystalline GaAs films are performed on SnO2-coated glass and Ti substrates. Energy spectrum analyses are used to measure deposition on film materials.

A new method which uses glow-discharge plasma for the deposition of thin yttria-stabilized layers was presented. The method utilized a dc bias circuit distinct from the plasma-generation circuit for the deposition process. The glow-discharge plasma method was able to produce a smooth, defect-free yttria stabilized zirconia film.

Microelectrodes that exhibited structural sizes reaching 400 nanometers in diameter were successfully made from flame-etched carbon fibers. Subsequent application of poly(oxyphenylene) coatings facilitated the copolymerization of phenol and 2-allylphenol on the surface of the electrode. The polymer deposition time, electrodeposition solution pH and phenol-allylphenol concentration were found to significantly affect the outcome of the insulating copolymer film.

Patterned arrays of magnetic elements may be useful as media for high density magnetic storage applications. Interferometric lithography has been used to fabricate arrays of cobalt and nickel pillars with periods of 200 nm over areas of 5 cm x 5 cm using a UV laser. This provides an economical and rapid method for manufacturing particle arrays. Index terms - electrodeposition, interferometric lithography, patterned media, nanomagnet

Arrays of semi-metallic Bi nanowires have been successfully fabricated by electrodeposition. A very large positive magnetoresistance of 300% at low temperatures and 70% at room temperature with quasi-linear field dependence has been observed. These features are highly desirable for magnetoresistive field sensing applications. Index Terms - electrodeposition, positive magnetoresistance, semi-metallic nanowires.

Magnetization reversal of individual Ni nanowires has been studied by anisotropic magnetoresistance (AMR) measurements. The wires are homogeneous cylinders 6[microns] long and averaging 80 nm in diameter. Nanowires were produced by electrodeposition in track-etched membrane templates. Electrical contacts to as-deposited single nanowires were obtained by a novel in-situ method where contact to a single wire is accomplished automatically and reliably during electrodeposition. Steps of the magnetoresistance are detected, corresponding to irreversible switching of the magnetization in a single wire. The dependence of the switching field on the orientation of the applied field as seen by AMR is identical to that recently observed by using micro-SQUID techniques. Index Terms - Anisotropic Magnetoresistance, Single Magnetic Nanoparticle Measurement, magnetization reversal, Curling.

Giant magnetoresistance (GMR) in Co-Ag multilayers and granular films produced by electrodeposition have been investigated. The Co-Ag alloy films have an fcc structure for the full range of compositions and no Co and Ag solid solution is formed. The deposition current density influences the magnetoresistance of Co-Ag single layer films giving a maximum magnetoresistance of 5% for a [Co.sub.32][Ag.sub.68] alloy film deposited at a current density of 10 mA/[cm.sup.2], measured at room temperature and within a 21 kOe field. GMR has also been observed for Co-Ag multilayer films. [Co.sub.rich]/[Ag.sub.rich] multilayer films show magnetoresistance values of 8.7% at room temperature and within a 21 kOe magnetic field.

Soft, high moment FeCoNi thin films were fabricated by pulsed-current electrodeposition, in which the period with current flow was in the range 0.5-20 s and period with no current flow in the range 0-30 s. Film composition is determined by two concurrent phenomena, anomalous codeposition and diffusion-limited reduction of Fe, whose relative importance can be controlled by adjusting the duration of the current pulses. For short current pulses and long intervals between pulses the anomalous deposition process dominates and the films are Fe-rich. Under these conditions, the ratio of BCC/FCC phases is also higher, which increases the saturation magnetization of the film. For long current pulses and short intervals between pulses the diffusion of [Fe.sup.2+] ions in the electrolyte dominates the reduction reaction. Correspondingly, the films are Ni-rich and the ratio of BCC/FCC phases is reduced. Index Terms--Fe-Co-Ni alloy, high magnetic moment, magnetic recording head, pulsed-current electrodeposition.

Controlling the very small amount of inclusion of impurity elements by addition to the plating bath of various organic additives was found to be very effective in developing electrodeposited high-[B.sub.s] CoNiFe soft magnetic thin films with desirably high resistivity. Included impurities were suggested to cause not only electron scattering but also decreasing grain size, both of which led to an increase of the resistivity. Chemical state of impurities was indicated to be controllable by selection of additives based on the functional group for adsorption. Index Terms--Electrodeposition, impurities, organic additives, resistivity, soft magnetic thin films.

Conventional microheat sink design primarily focuses on the use of continuous fin arrays to optimally dissipate thermal energy from electronic components. By contrast, this paper experimentally measures the thermal and structural performance of two micro pin fin heat sinks designed for use in load bearing applications such as mechanical seals and thrust bearings. One pin fin array is of low porosity, which is more optimal for load bearing capacity, and the other is of high porosity, which is more optimal for heat dissipation. By using these two extreme cases, the thermal-structural tradeoff found in load bearing microheat sinks is demonstrated. The heat sinks are constructed of nickel, electrodeposited onto a stainless steel thrust ring using a modified LIGA technique. Under forced air cooling, the thermal performance of each is compared to a simple model based on a combination of macroscale pin fin heat sink results and classical correlations for fins in cross flow. The low porosity design is also tested under the application of a 44.5 N thrust load at 2500 rpm and found to be structurally sound. Experimental temperature profiles demonstrate a substantial benefit of the microheat sink in cooling the load bearing surface. [601] Index Terms--Forced air cooling, mechanical seals, microheat exchanger, microheat sink, thrust bearings.

The electrodeposition method for repair of cracked reinforced concrete is presented here. Electrodeposition means precipitation of material on the surface of an electrode by electrolysis. The ultimate purpose of this study is to apply this technique to land-based reinforced concrete structures. Investigations on mortar specimens with embedded steel were conducted. After cracking the specimens with a specified load, they were immersed in several types of solutions. Then a constant current between the embedded steel in mortar and an electrode in the solution was applied. The deposition pattern on the surface, the crack closure development, and surface coating due to the precipitation of electrodeposits were checked and evaluated. In order to assess the effectiveness of this method to improve the mortar surface, water permeability, pore size distribution, and adhesion strength were measured. The results indicate that electrodeposits formed on the mortar surface are able to close the crack and coat the mortar surface. In addition, the investigations show that the deposition product can improve the microstructure of the mortar surface.

The electrodeposition of Co-Fe and Co-Fe-Ni alloys from electrolytes without any organic additives is explored. For Co-Fe alloys, the effect of the ratio of Co and Fe concentrations in the electrolyte on the composition and magnetic properties of the deposits is examined. A maximum saturation magnetization of 20.4 kG is obtained, however the films showed high coercivity (20 to 30 Oe). The addition of Ni to the solution leads to much improved soft magnetic properties. A Fe-rich alloy, [Co.sub.19][Fe.sub.52][Ni.sub.29] showed a saturation magnetization of 20.5 kG, a coercivity of about 1 Oe and saturation magnetostriction [[Lambda].sub.s], about [10.sup.-6]. Best soft magnetic properties are obtained when BCC and FCC phases are seen to coexist. The films show good stability of magnetic properties upon easy axis annealing up to 200 [degrees] C. Magnetic force microscopy showed the domain pattern to be a ripple structure for films with positive magnetostriction, changing to a stripe domain structure with increasing Ni content. This corresponds to a change in sign of the magnetostriction. Index Terms--Co-Fe alloy, electrodeposition, magnetic recording head, Ni-Co-Fe alloy, soft-high magnetization material.

We report comprehensive experimental studies on ballistic magnetoresistance (BMR) in nanocontacts of different materials. We show that BMR values [is greater than] 200% can be achieved in ballistic nanocontacts of ferromagnet such as nickel and cobalt whilst the nanocontacts of dirty ferromagnetic materials such as Heusler alloy exhibit very small magnetoresistance (MR) at room temperature (RT) and low applied field. The reason for this is that, the BMR is a nonadiabatic process, but in the dirty cases the domain wall (DW) thickness [Lambda] is larger than the mean free path l for spin reversal hence the electrons can adiabatically follow the magnetization change when they traverse the DW resulting in negligible DW scattering. We also show that in an electrodeposited stable nanoscopic nickel contact it is possible to manipulate the MR by applying current pulses and external magnetic field. We discuss the origin of this effect in terms of combined effect of current induced and external field. Index Terms--Ballistic magnetoresistance, domain wall, electrodeposition, magnetoresistance manipulation.

Electrodeposited spin-valves on GaAs substrates were patterned down into 80 gm, 4 [micro]m and 2 [micro]m strips. A symmetric spin-valve configuration is used which incorporates an artificially hard substructure. Sensitivities up to 1.5%/Oe were observed, these being the highest ever observed in electrodeposited structures. Upon patterning an increased antiferromagnetic contribution of the inner hard substructure was seen. Index Terms--Anisotropy, Electrodeposition, Co/Cu layers, Patterning, Spin-valves.

A method for electrochemically depositing nanometer-scale patterns of silver from a scanning tunneling microscope tip in air was presented. The method involved two steps in which patterns are prepared within a 2-nm-thick self-assembled monolayer resist confined to a gold(111) substrate, followed by the electrochemical deposition of Ag into the previously formed patterns. In the second step, no deposition occurred on the passivated portion of the resist. Results focus on the simplicity of the method and the effectiveness of the tip to effect area-selective deposition.

Mirrors that exhibit mid-to-high-frequency (3 x [10.sup.-4] to 0.1-[[Mu]m.sup.-1]) roughness as low as 3 A were produced by nickel electroform replication by using a sapphire master. The fabrication procedure and potential applications in x-ray astronomy are discussed.

NIST researchers have quantified the link that exists between chemical vapor deposition and liquid solution electrodeposition for superconformal filling of high-aspect ratio, fine features. This recent work exploits the curvature […]

NIST metallurgists have for the first time applied the phase field method to the modeling of electrochemical processes. This method employs a phase-field variable, a function of position and time […]

The diffusion-limited corrosion of porous copper clusters in thin gap cells containing cupric chloride were subjected to experimentation. The process was well-described by one-dimensional mean-field model for the generic reaction A + B(static)->C(inert) with only one diffusing reactant and one static reactant reacting to produce an inert product. This was obtained by careful comparison of corrosion front velocities and concentration profiles from phase-shift interferometry with theoretical predictions.