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Noise suppression effect of Co-Pd-Al-O nanogranular thin films, which have considerably high permeability up to gigahertz range, was investigated. The films with large variety of electrical resistivity (/spl rho/) from 10/sup 2/ to 10/sup 7/ /spl mu//spl Omega//spl middot/cm were prepared by reactive sputtering method and by changing both target compositions and deposition conditions. The films with /spl rho/ less than 10/sup 3/ /spl mu//spl Omega//spl middot/cm are ferromagnetic, and the films with /spl rho/ more than 10/sup 6/ /spl mu//spl Omega//spl middot/cm are superparamagnetic. A microstrip line with granular films placed on its top was used to evaluate conduction noise suppression. The result of transmission and reflection measurements reveals that these nanogranular soft magnetic Co-Pd-Al-O thin films have high potential for noise suppressors in the gigahertz range. In particular, the broad maximum of power loss (P/sub loss//P/sub in/) about 0.6 at 6 GHz has been obtained in Co-Pd-Al-O films with /spl rho/ around 10/sup 4/ /spl mu//spl Omega//spl middot/cm.

The microstructures of Co–Al–O thin films of wide varieties of compositions are studied by transmission electron microscopy and small angle x-ray scattering (SAXS). In the superparamagnetic specimens, high resolution electron microscope images reveal that isolated spherical Co particles are surrounded by an amorphous aluminum oxide matrix. However, in the soft ferromagnetic films, the shape of the Co particles is prolate ellipsoidal. SAXS intensities from the soft magnetic specimens decrease inversely with the wave vector, q, in a low wave-vector region, while an interparticle interference peak is observed for the superparamagnetic specimens. The scattering profiles of the soft magnetic films imply that the Co particles have a cylindrical shape and are randomly oriented. The correlation between the magnetic properties and the microstructures is discussed.

Several Co-Al-O alloy thin films with different physical properties were prepared by reactive r.f. sputtering of Co 85 Al 15 and Co 70 Al 30 alloy targets in Ar + O 2 atmospheres and were characterized by XPS, x-ray diffraction (XRD) and electron probe microanalysis (EPMA). The alloy films contained metallic Co, mainly of hexagonal phase, and also CoO. The Al oxide in the Co-Al-O thin films did not give any detectable diffraction peaks. The EPMA results showed that [Al]/([Co] + [Al]) ratios, where [M] denotes molar fraction of element M in the alloy, were almost the same as the compositions of the targets used for sputtering. However, quantitative XPS analysis resulted in much higher values of [Al]/([Co]+ [Al]) ratios in comparison with the bulk values, suggesting enrichment of Al in the surface region. Aluminium detected by XPS was all in the oxidized state, and was in the form of hydroxide in the top surface region. Cobalt in the topmost region was in the form of oxybydroxide, which was easily reduced to the metallic state by Ar + etching. By taking the XPS, XRD and EPMA results into consideration, the difference of Co-Al-O alloys in electric resistance was explained qualitatively by the difference in microstructure of the alloy films, i.e. the difference in thickness of the oxide films on nanoscale particles of metallic Co embedded in an oxidized Al matrix together with the clearance between the nanoscale Co particles.

Recent advances in the researches of tunnel-magnetoresistance (tunnel-MR) in metal–nonmetal granular systems are overviewed, showing mainly our results on Co–Al–O films. Electron microscopy observations revealed that sputter-deposited Co–Al–O films possess well-defined metal–nonmetal granular structures with Co granules of 2–3 nm in diameter. Anomalous temperature and bias-voltage dependence of MR was found in Co–Al–O granular films, and was explained by a theory of spin-dependent higher-order tunneling. Magnetic field sensitivity of tunnel-MR in metal–nonmetal granular systems was dramatically improved by means of granular-in-gap (GIG) structures. Perspectives for the future application are also discussed with GIGs.

The low-field-magnetoresistive (MR) response of the tunnel-type magnetoresistance (TMR) of metal-nonmetal granular film was examined. The MR ratio at 500 Oe of (Fe75Al25)-O films prepared by a tandem deposition method increases with increasing Fe grain size and begins to decrease at more than 2.0 nm. This suggests that there is a limit to the improvement in the MR that can be obtained by controlling the film structure. On the other hand, the magnetoresistance of GIG (nano-Granular In Gap) film consisting of soft magnetic and granular TMR films exhibits a huge field response in a low magnetic field. The MR ratio of GIG film consisting of a-Co77Fe5Si9B9 and Co39Y14O47 films at 2.5 Oe is more than 2.4%, which is about 250 times larger than that of a Co39Y14O47 single-layered film. GIG film consisting of a-Co77Fe5Si9B9 film shows a lrager response of the magnetoresistance in a low magnetic field than GIG film consisting of Fe66Ni34 film, because the coercivity of a-Co77Fe5Si9B9 film is lower than that of Fe66Ni34 film.

We investigated the use of planar-type inductors containing Co based soft magnetic films, which have highly electrical resistivity, as magnetic cores. Inductors were fabricated by using an RF magnetron sputtering method and a lift-off technique. Realizing smaller magnetostriction composition in a magnetic core is a major factor in obtaining a high quality factor (Q) in a inductor. Multilayering a zero magnetostrictive Co-based film with SiO2 film is an effective means of obtaining soft magnetic films at low substrate temperatures. A composite multilayered film consisting of thin and thick SiO2 films proved to be an excellent soft magnetic film with very low eddy current loss and loss due to a resonance. The highest values of Q and the inductance of the inductor, which were obtained by using a composite multilayered film subjected to rotational field annealing, were 25.5 and 26 nH at 180 MHz, respectively.

A very high response of the tunnel-type magnetoresistance at low magnetic fields for metal and nonmetal granular thin films was achieved by constructing the following hybrid structure: a large TMR Co-based metal–nonmetal film was placed in the lateral gap between a couple of soft magnetic permalloy, Fe 66 Ni 34 , films. We call our hybrid structure `nano-granular in gap (GIG)' film. This film was prepared by a micro processing technique using ion milling and RF sputtering methods. The best MR values obtained at about 2 Oe were 2–3% for a Fe 66 Ni 34 –Co 39 Y 14 O 47 –Fe 66 Ni 34 GIG film, which was about 250 times larger than the value for a single-layered film of Co 39 Y 14 O 47 . This huge enhancement was attributed to the effect of the strong magnetic flux created at the narrow space between the coupled soft magnetic Fe 66 Ni 34 films by small applied magnetic fields.

Thin (Co0.8Al0.2)100−xNx (x=0–30 at.%) alloy films prepared by a reactive radio frequency (r.f.) sputtering method were characterized by XPS and x-ray diffraction (XRD). The film with no nitrogen consisted of a CsCl-type CoAl metallic compound, while the nitrogen-containing alloys were composed of very fine AlN and face-centred cubic (fcc) Co phases. The quantitative XPS analysis under an assumption of uniform distribution of all the elements resulted in much lower concentrations of Co and higher concentrations of Al and N in comparison with the bulk composition for the nitrogen-containing alloys. By taking account of the granular structure of the alloy films, i.e. the nanoscale particles of fcc Co embedded in the AlN compound, the results of quantitative XPS analysis were explained successfully. Moreover, the thickness of the AlN layer and the size of the fcc Co particles were also able to be estimated under the nanoscale structure models. The results were in good agreement with observation by transmission electron microscopy, especially when a nanostructure model was adopted where nanoscale Co–N particles are dispersed in AlN matrix in a simple cubic-like arrangement. © 1998 John Wiley & Sons, Ltd.

The relationship between the giant magnetoresistance (GMR) and the nano-granular structure of (Fe, Co)/Al2O3 films prepared by a tandem deposition method was examined. The structure of the films was controlled by changing the rotation speed of a substrate holder. In this way, the size of the metallic granules in the film was changed independently of the film composition. In the case of Fe/Al2O3 films, the average diameter of a metallic granule decreased from 2.5 to 1.5 nm with an increase in the rotation speed of the substrate holder. On the other hand, the width of the Al oxide boundary among metallic granules was estimated to be about 0.5-1 nm. The MR ratio increased with a decrease in the size of the metal granules. So-called coulomb blockade effect is discussed the influence of the granule size on the MR ratio.

The alkylation of ethyl (S)- and (R)-4,5-epoxy-2-pentenoates (11) and (12), chiral terminal γ,δ-epoxy acrylates prepared from D-mannitol, by trialkylaluminum in the presence of water occurs regioselectively at the γ position, i.e., at the internal position, to yield a sole product respectively with net inversion of configuration. The method provides useful chiral synthons for natural product synthesis.

We studied giant magnetoresistance (GMR) and the related properties in Co-Al-O insulating granular films prepared by reactive sputtering. Microstructural observation revealed that the films were composed of Co base metallic granules and Al2O3 base insulating network-like boundaries. The GMR varied as a function of oxygen content (or Co/Al2O3 ratio) and it took a maximum of 8% at room temperature and 17% at 4.2 K for a Co52Al20O28 film, accompanying huge specific electrical resistivities of the order of 105–106 μΩ cm. It has been considered that the observed GMRs are attributed to a spin-dependent tunneling and that the spin diffusion of electrons during tunneling plays an important role of the composition dependence of GMR. In addition, it has been noted that the temperature dependence of GMR is smaller than the T−1 dependence predicted theoretically by Helman et al. but rather close to the theory by Inoue et al.

CoAlO thin films, with network-like nano granular structure consisting of Co based magnetic and metallic grains and A1 2 O 3 based nonmetallic intergrains, were fabricated by Ar + O 2 reactive sputtering. Giant magnetoresistances (GMR) were observed. From the experiments on oxygen concentration dependence of GMR, electrical resistivity and microstructure, it was confirmed that spin dependent tunneling was responsible for the GMRs.

We have developed a pixel-type two-dimensional position sensitive Li-glass neutron detector for high rate application, which would be useable for time-of-flight radiography, namely transmission spectroscopy. The pieces of Li-glass were attached directly to a 8×8 channel photo multiplier. We measured its performance at KEK and Hokkaido University. The count rate of this detector was found to be about 8.3 Mcps/cm 2 (240 Kcps per pixel). The efficiency of the detector corrected for the effective detection area is 100% over 9 A and 95% at 3 A. The difference in the count rate of each pixel was very small, less than 2%.

Previously, a tunnel type of giant magnetoresistance (GMR) was discovered in a sputtered Co-base CoAlO granular alloy thin film, which was characteristic in exhibiting GMR of about 8% accompanying a large specific electrical resistivity of the order of 10 4 μΩ cm, due to a weak tunnel conductance in the metal-nonmetal granular structure of this alloy. In this paper, it has been found that GMR changes depending on O content and appears with a maximum near the percolation threshold point from metallic conductance to tunnel conductance in CoAlO granular alloy thin films. In addition, superparamagnetic behavior in the magnetic field and temperature dependencies of magnetization have been found for the GMR alloy films. The observations support the spin-dependent tunneling effect for this new GMR.

This paper studies the effect of magnetic field annealing on the structure and properties of highly electrically resistive Co-based soft magnetic films, prepared by RF reactive magnetron sputtering with (N2+Ar) gases. After annealing near 300°C in a static magnetic field, Co-Al-N films whose nitrogen content is lower than their Al content exhibit almost exactly the calculated μ-f characteristics. TEM observation reveals that these films are granular with a very fine network structure, which has a considerable number of connections among granules. With increasing nitrogen content, the size of the granules decreases, and the intergranule composition approaches that of AlN. It follows that improved μ-f characteristics can be obtained in Co-Al-N film of an appropriate composition and structure.

This paper reports on an IR study (5–20 µm) of the dispersion and field dependences of the magnetorefractive effect in granular CoFe-MgF (metal-insulator) systems, which exhibit, in compositions close to the percolation threshold, a tunneling magnetoresistance of 7.5% in a field of 1700 Oe. The change in the reflectivity of p-polarized light under magnetization in the IR spectral region 5–7 µm is of the order of 0.1%, while in the 10-to 12-µm region, this change, reaches record-high values of 1.2–1.5%, which exceed the usual odd and even magnetooptic reflectivities in the IR range by two orders of magnitude. The magnetorefractive effect in magnetic systems with tunneling conduction originates from spin-dependent high-frequency tunneling.

The effects of the Al and N content on the structure and properties of Co .95 Fe .05 -Al-N films prepared by rf reactive magnetron sputtering using (N 2 +Ar) gas were studied. TEM observations revealed that nitrided films are composed of heterogeneous phases with a very fine network structure. It was found that the properties of films are determined mainly by the combination of the Al and N concentrations. The coercivity of films containing more than 10 at% Al decreases with increasing N content, even when the film thickness is more than 2 ?m. A steep increase in the electrical resistivity and a slight decrease in the magnetization of films containing more than 15 at% Al were observed during the initial increase in the N concentration, and both electrical resistivity and magnetization decreased rapidly when the N concentration was the same as that of Al. These anomalies are attributed to intergranular materials, indicating the presence in these films of a phase rich in Al and N.

Fe-M-(O, F) (M=Si, Mg, Y, Zr, Ca, Al) films were prepared by co-sputtering of Fe and ceramic targets. These films have a network-like structure composed of metallic fine grains with a diameter of about 50∼100A and ceramic-like boundaries. Those films that consist of bcc-Fe grains have soft magnetic properties and low magnetostriction in the as-deposited state. Their permeability has a good frequency response, which seems to be attributable to the reduction of eddy current losses by the highly resistive boundaries.

FeBN and FeBNO films were prepared by co-sputtering of Fe and boron nitride (BN) targets in an Ar atmosphere and an ArO2 atmosphere respectively. In the as-deposited amorphous state, their electrical resistivity ϱ increases with increasing O2 flow ratio in the sputtering gases. FeBN films have a positive large saturation magnetostriction λs as ordinary Fe-based amorphous alloys do, but the addition of oxygen decreases λs. These films are crystallized into the b.c.c. Fe phase by annealing. The crystallized FeBNO films exhibit good soft magnetic properties with high ϱ and low λs (H ≈ 0.1 Oe; μ ≈ 1500; ϱ ≈ 1500 μω cm; λs ≈ + 5 × 10−6). These soft magnetic properties and lower magnetostriction are attributed to fine b.c.c. Fe grains surrounded by ceramic-like boundaries.

The structure and properties of Co 95 Fe 5 MeN films (M ≡ Al, B or Si), prepared by r.f. reactive magnetron sputtering with N 2 Ar gases, have been studied. Transmission electron microscopy observation reveals that the nitrided films are composed of a very fine network of heterogeneous phases. The electrical resistivity of films increases with increasing nitrogen flow ratio in the sputtering gas (ArN 2 ) and is attributed to the refinement of structure due to nitridation. The films containing Si or Al exhibit soft magnetic properties, characterized by a good frequency response of permeability. The existence of a larger amount of M further increases the resistivity, suggesting that the presence of the MN phase plays an important role in high resistivity.

Following the high electrical resistivity of heterogeneous alloys found recently for high frequency materials useful at 1–500 MHz, the detailed behaviour of the resistivity has been studied in Co80Al20N, Co80Al20O and (Co0.9Fe0.1)70B30O sputtered thin films. The electrical resistivity increases from 102 to 1012 μω cm with increasing concentration of N (or O), showing an abrupt increase at a critical concentration. The temperature dependence of the resistivity changes significantly with N (or O) content except for CoAlN alloys. For alloys near the critical concentration a resistivity minimum appears at a temperature between 30 and 260 K, while the resistivity at lower temperatures follows −logT. In contrast, a tunnelling-type temperature dependence described by exp (T − 1 2 ) is observed for higher N (or O) alloys. It is considered that a weakly conductive network consisting of a heterogeneous mixture of metallic and non-metallic phases, i.e. the percolation of electrical current through this network, governs the resistivity observed.

Fe-N films were synthesized by means of ion beam deposition. Nitridation was performed using an assist gun during the sputtering of Fe films. The as-deposited Fe-N films consisted of two phases, ?-Fe and ?'-Fe 4 N, and had a high coercive force H c of over 20 Oe. When the films were annealed in vacuum, their H c improved drastically, and had a minimum value of less than 1 Oe at 400°C. The films also had a high permeability of over 2000 as well as high resistivity (around 80 ??-cm), in spite of a high saturation magnetization (around 18 kG). The small grain size and stress relaxation in the films are closely related to the soft magnetic properties. The volume fraction of the ?'-Fe 4 N phase also affected the decrease in H c , because the anisotropy normal to the film plane is reduced by increasing the magnetostatic energy when the volume fraction was 0.5.

The magnetic and structural properties of multilayered CoBN/AIN films prepared by sputtering were investigated with the intention of creating film suitable for application in micromagnetic devices operating at high frequencies. A CoBN single-layer film has a resistivity ? of about 340 ??-cm, a B s of about 10.3 kG, and perpendicular magnetic anisotropy. CoBN/AIN multilayer films, even when the AIN layer thickness is about 3A, exhibit soft magnetic properties (H c ≪1 Oe and ?≫500) for a variety of layer thickness combinations. SEM observations suggest that the soft magnetic properties of the multilayer films originate in their in-plane uniaxial anisotropy and in the fine grains in the CoBN layers. The magnetostriction of multilayer films ranged between ±1×10-6, and the anisotropy field was over 15 Oe. Although film thicknesses exceeded 2 ?m, a high permeability ? was maintained, even at frequencies close to 300 MHz.

In an effort to obtain a high-quality magnetic thin film for use in micro-inductors, the magnetic and structural properties of highly resistive Fe-BN films were studied. In the case of films deposited on substrates electrically isolated from ground, the B s value, resistivity, and H c all varied as functions of the sputtering gas pressure (P s ). The structures of as-deposited films were amorphous, and on annealing they crystallized into an ?-Fe single phase. On the other hand, the above parameters were independent of P s for films deposited with a negative bias voltage applied to the substrate. These films were also amorphous in the as-deposited state, and crystallized into Fe 3 B and ?-Fe on annealing. XPS analyses revealed that application of a negative bias voltage decreased the N and O contents, and especially the concentration of BN, in these films. This finding is attributed to the enhancement of Ar+ ion bombardment at the time of deposition.

A measurement method for measuring radon in water using the portable radon survey meter (RnSM) was developed. The container with propeller was used to stir the water samples and release radon from the water into the air in a sample box of the RnSM. In this method, the measurement of error would be20 %, when the radon concentration in the mineral water was20 Bq l(-1).

Based on the perturbation theory with multiple scales, we have developed a technique to study the evolution of particle distribution as a function of oscillation amplitudes in a hadron storage ring. With a renormalization scheme for the zeroth-order term, a uniformly valid perturbation expansion for the distribution function is obtained. For localized nonlinear perturbations such as the beam-beam interaction at colliding points, this renormalization scheme results in a functional mapping for the particle distribution and the diffusion processes of particles in the beam can be studied numerically without resorting to the tracking of individual particles. A case involving a single nonlinear kick in the ring is presented to illustrate the method in detail.

A thin-film 3.14-mm*3.88-mm microtransformer has been fabricated, using photolithography technology, to support high-frequency switching regulators. The microtransformer is composed of sputtered amorphous magnetic layers, electroplated copper windings with 20- mu m width, and insulator layers. The coupling factor between the primary and secondary windings of the microtransformer is 0.97 for f=3 MHz. An input-output voltage ratio of 0.95 at 15 MHz is obtained at no-load. Observation of the domain images under high-frequency excitation indicates that the magnetic anisotropy of the microtransformer films is induced by rotating magnetic field annealing so as to increase the output voltage. >

The alkylation of ethyl (S)- and (R)-4,5-epoxy-2-pentenoates (11) and (12), chiral terminal γ,δ-epoxy acrylates prepared from D-mannitol, by trialkylaluminum in the presence of water occurs regioselectively at the γ position, i.e., at the internal position, to yield a sole product respectively with net inversion of configuration. The method provides useful chiral synthons for natural product synthesis.

Magnetic properties and structure of FeN/AlN multilayered films deposited by r.f. magnetron sputtering were studied. Hc decreased as the ratio of a FeN layer thickness to a AIN one became small. Hc also decreased with decreasing film thickness of FeN/AIN bilayers. Hc and 4 πMs in a 22A/11A multilayered film were 1 Oe and 8.5 kG, respectively. The film had high permeability, μ', which was 800 at a 5 MHz and 650 even at a 100 MHz because of high resistivity. SEM observation and μ-AES analysis revealed the film had a layered structure. X-ray diffraction made it clear that high permeability was ascribed to fine grains and smaller lattice mismatch between layers compared to the thick layered films.

stract-The magnetic and structural properties of multilayered FeN/FeBN films prepared by dual-target sputtering were investigated. Laminating FeBN films with FeN films increases the electrical resistivity (R) by up to 200 ??-cm, decreases slightly the saturation magnetization and results in excellent soft magnetic properties (coercivity ?0.2 Oe and permeability ?1000) over a wide range of film thickness combinations; this despite the fact that single FeBN films have a high R of about 400 ??-cm, a B s of about 12 kG and semi-hard magnetic properties with perpendicular magnetic anisotropy. SEM observations suggest that the soft magnetic properties of FeN/FeBN multilayer films originate in their in-plane anisotropy and the fine grain texture of the films. Despite film thicknesses exceeding 2 ?m, a permeability of about 1000 was maintained even near 100 MHz. The extended frequency response of the permeability is without doubt due to the increased electrical resistivity of films when laminated with FeBN.

The crystal structure and magnetic properties of sputter-deposited Fe-Si-N films were investigated. Fe-Si-N films had a single ?-Fe phase, and with higher N content, two phases, ?-Fe and ?'-Fe 4 N. A coercivity H c lower than 1 Oe was obtained for single ?-Fe phase films. The permeability ? was found to be strongly related to the substrate temperature T sub during deposition. For example, deposition at T sub =230°C gave rise to ?=3600 at 10 MHz. Such high values were obtained in single ?-Fe phase films, which consisted of fine crystal grains with a (111) plane orientation. The permeability of films with a high Si concentration was found to have high thermal stability.

Magnetic and structural properties of multilayer FeSiN/ceramic films produced by dual-type sputtering were investigated. Laminating of FeSiN with ceramic layers enhanced not only the frequency response of the permeability ?, but also the value of ?. These soft magnetic properties of as-deposited films were found to be strongly related to the substrate temperature T sub , but were independent of the kind of ceramic used. Multilayered FeSiN/AIN films deposited at T sub =300°C exhibited a large ? (at 5 MHz) of about 5,000 and a saturation induction B s of more than 17 kG. SEM observation suggested that the soft magnetic properties of FeSiN-base multilayers arise from the decrease in magnetic anisotropy of the assembly of magnetically interacting small grains, and also from the (111) plane orientation of the grains. Most multilayered films exhibited greater thermal resistance to aging up to 600°C, because the ceramic layers prevent the growth of ?-Fe grains.

In efforts to obtain excellent-quality magnetic thin films for use in micro-inductance cores, amorphous Co-base films containing fine dispersed nitride particles were investigated. Sputter-deposited films were confirmed to have an amorphous structure, near-zero magnetostriction (?) and high electrical resistivity. TEM observations clarified that films were composed of two kinds of amorphous phase. The soft magnetic properties of films were found to be related to the film thickness: at thicknesses below 0.1 ?m, films became magnetically soft. Based on this relation, we attempted to prepare multilayered films consisting of thin Co-base layers and thin BN ceramic layers, and obtained excellent properties as a result, with a high ? (≫300 ??-cm), low ? (1×10-6) and high ? (≫1000) at high frequencies near 100 MHz.

In this work, thin film microinductors were investigated from the standpoint of increasing the quality factor (Q) and inductance (L). To obtain a high Q, it is important to use a magnetic core with a small iron loss at high frequencies. Thin film microinductors were prepared using multilayered CoNbZr/AlN film. The optimum conditions for a high Q were investigated by changing the size of the magnetic core and the structure of the multilayer film and exciting coil. The Q and L values increased with decreasing thickness of individual magnetic layers and with increasing intermediate layer thickness. The demagnetization of the inductor open magnetic circuit was decreased by using a multilayer magnetic core. The stray capacitance between coil and magnetic core is dominant in these thin film inductors. It was found that multilayer magnetic core is useful for increasing the Q and L values of thin film inductors at high frequencies. An experimental inductor in which iron and copper losses were reduced through the use of a multilayer core and thick coil had an L=120 nH and Q=18 at 50 MHz, and measured 0.5 mm × 2.5 mm × 35 ?m.

The dependence of the magnetic properties of multilayer CoNbZr/AlN films on the conditions of film preparation was investigated. AlN films were prepared by N 2 reactive sputtering deposition on CoNbZr films. The soft magnetic properties of the as-deposited films were found to be strongly related to the rf input power during AlN deposition. The anisotropy field decreases drastically at an input power of greater than 2 W/cm2, and a high permeability of around 10,000 (at 5 MHz) was obtained for as-deposited films prepared at an rf input power during A1N deposition of 4.4 W/cm2. SEM observations revealed that CoNbZr films in as-deposited multilayer form have nearly the same morphology as amorphous alloy films annealed at the optimum temperature for reduction of the anisotropy field. The annealing process during film preparation (self-annealing effect) is attributed to the heat generated during AlN deposition, originating mainly in the heat of formation in AlN reactive sputtering.

Magneto-optical spectra of the insulating granular system Co–Al–O prepared by reactive sputtering are measured in the energy range 0.5–3.8 eV. The transverse Kerr effect magnitude in the Co 52 Al 20 O 28 film attain large values. The data have been interpreted in the framework of the effective medium approximations: Bruggeman (BA) and symmetrised Maxwell–Garnett approximation (SMG). The best fit between experimental data and theoretical prediction was obtained in SMG. It is shown that magneto-optical spectra of ferromagnetic composites are highly sensitive to composite microstructure.

We have investigated the magnetic properties of (Co1−xFex)–Al–O granular thin films prepared by a reactive sputtering method in an atmosphere of O2+Ar. The coercivity and electrical resistivity of the films are almost independent of x, but with increasing x the anisotropy field decreases linearly and the saturation induction has a broad maximum of 20 kG around x=0.7. The granular films show the same general tendency as bulk Co–Fe alloys in the compositional dependence of magnetostriction (λ). The magnitude of λ varies with increasing annealing temperature. Using a film with x=0.08 as the core of a spiral-wound inductor gave a quality factor Q=25 at a frequency of 300 MHz.

Optical and magneto-optical spectra of the insulating granular system Co-Al-O prepared by reactive sputtering are measured in the energy range 0.5-3.8 eV. The trans- verse Kerr effect magnitude in the Co52Al20O28 film attain large values. The data have been interpreted in the frame- work of the effective medium approximations: Bruggeman (BA) and symmetrised Maxwell- Garnett approximation (SMG). The best fit between experimental data and theoretical prediction was obtained in SMG. It is shown that magneto-optical spectra of ferromagnetic composites are highly sensitive to composite microstructure.

The relationship between the tunnel-type magnetoresistance(TMR) and the structure of metal-nonmetal granular system (Fe-Co)-Al-O films has been examined. Films were prepared by a tandem deposition method with rotating a substrate holder. The average diameter of metallic granules is found to decrease with an increase in the rotating speed of substrate holder without any change of film composition. And the MR ratio increases with a decrease of the diameter of metallic granules. The influence of the granule diameter on the MR ratio is discussed by so-called coulomb blockade effect. Furthermore, we studied the effect of a substrate temperature(Tsub.) on the MR and the structure of films. The MR ratio and electrical resistivity of the films increase with an increase of Tsub.. The magnetization measurements suggests that these increases are related with the decrease of the amount of magnetic impurities in the Al-oxide intergranule. The phase separation between the metallic granule and the oxide intergranule may take place in the film prepared on the higher Tsub..

A study was made of the properties and structure of Co-Si-Pd-O based films, prepared by reactive sputtering method Soft magnetic properties are found in the films with O content at the percolation threshold, and realized in the composition range more than 2%Si and 5%Pd in Co- Si-Pd-(O) pseudo-ternary system films. A larger Hk than 200 Oe is attained in the soft magnetic films near 8%Si and more than 10%Pd, where ρ is about 1000 μΩcm. The compositional dependence of these properties except Hk can be explained by the structure change with composition. A large Hk can be easily controlled by magnetic annealing from 0 to more than 200 Oe, which originates in the induced magnetic anisotropy.

Dependence of magnetic properties and Kerr effects in PtMnSb thin films on oxygen partial pressure during annealing was investigated. The coercivity H c? increased with oxygen partial pressure, while the change in H c? was relatively small. The saturation magnetization M s was almost constant up to 6 × 10?4 Torr, and then decreased rapidly at higher O 2 pressures. The Kerr rotation angle in zero magnetic field ? K(0) and the squareness ratio R s of Kerr loops took on maximum values at or near 8 × 10?4 Torr of 0.85° and 0.45 respectively. SEM observations and X-ray diffraction studies revealed that these values are related to the preferential oxidation at PtMnSb columnar boundaries. The oxidation may shorten the size of columns and isolate them from each other.

Magnetic properties and noise suppression effect of Co85B15-Pd-O soft magnetic nano-granular thin films were investigated. Films with a wide compositional range were prepared by the reactive sputtering method. Soft magnetic films were obtained in the compositional range with the O content more than the Co-Pd-B2O3, where there can be simultaneously obtained rho with a range from 103 to 105 muOmegamiddotcm, Bs of 8-9 kG, and Hk around 100-150 Oe. A microstrip line with nano-granular film placed on its top was used to evaluate the conduction noise suppression by measuring the transmission and reflection of electromagnetic wave. The result reveals that soft magnetic Co85B15-Pd-O films have a high potential for noise suppressors, which is six times larger than that of the Film Impedor commonly used as a noise suppressor at high frequency, in all measured frequency range

In a four month study, a design for a Proton Driver was developed as a possible replacement for Fermilab's Booster. Its optical properties are summarized briefly.

The Department of Energy has initiated its Stockpile Stewardship and Management Program (SSMP) to provide a single, integrated technical program for maintaining the continued safety and reliability of the nation's nuclear weapons stockpile in the absence of nuclear testing. Consistent with the SSMP, the Advanced Hydrotest Facility (AHF) has been conceived to provide improved radiographic imaging with multiple axes and multiple time frames. The AHF would be used to better understand the evolution of nuclear weapon primary implosion shape under normal and accident scenarios. There are three fundamental technologies currently under consideration for use on the AHF. These include linear induction acceleration, inductive-adder pulsed-power technology (both technologies using high current electron beams to produce an intense X-ray beam) and high-energy proton accelerators to produce a proton beam. The Scrounge-atron (a proton synchrotron) was conceived to be a relatively low cost demonstration of the viability of the third technology using bursts of energetic protons, magnetic lenses, and particle detectors to produce the radiographic image. In order for the Scrounge-atron to provide information useful for the AHF technology decision, the accelerator would have to be built as quickly and as economically as possible. These conditions can be met by "scrounging" parts from decommissioned accelerators across the country, especially the Main Ring at Fermilab. The Scrounge-atron is designed to meet the baseline parameters for single axis proton radiography: a 20 GeV proton beam of ten pulses, 10/spl deg/ protons each, spaced 250 ns apart.

A conceptual lattice design for a very compact superconducting synchrotron dedicated to X-ray lithography is presented. The synchrotron radiation produced in the high field superconducting magnets has a critical wavelength of 10 AA at a beam energy of about 787 MeV. The size and angular divergence of the beam in this lattice can satisfy the future requirements for X-ray lithography: sigma /sub x,y/ >