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The photorefractive properties of the iron-doped Pb(Zn1/3Nb2/3)O3-PbTiO3 (PZN-PT) relaxor ferroelectric single crystals were investigated by two-beam coupling experiments. The Fe:0.01 wt %- and the Fe:0.1 wt %-doped 0.91PZN-0.09PT single crystals were grown with the flux solution method. The Extinction spectrum, the electro-opric coefficient, the light-induced absorption change, and the photoconductivity were measured in these samples. The maximum gain coefficient reached to 21 cm-1, which is about twice as large as that of undoped PZN-PT. The grating formation rate decreases with the Fe concentration. [ABSTRACT FROM AUTHOR]

An investigation was made of the magnetic properties of Nd-Fe-Co-V bulk exchange-spring magnets fabricated by spark plasma sintering and consisting of a hard Nd[sub 2]Fe[sub 14]B phase and a soft α-Fe phase and having a low rare-earth content of Nd = 2-7 at. %. The high saturation magnetization of the bulk exchange-spring magnets was confirmed experimentally, and the measured data agreed well with the saturation magnetization values estimated from their respective rare-earth content. The saturation magnetization values were nearly uniform and were not dependent on changes in the grain size. Additionally, the specific resistance of the samples nearly coincided with the values interpolated from the specific resistances of an ordinary sintered pure Fe bulk compact and a sintered Nd-Fe-B magnet. These results suggest that the α-Fe/Nd[sub 2]Fe[sub 14]B bulk exchange-spring magnets did not contain any appreciable grain boundary phase between the fine nanoscale-size grains or tertiary phase. [ABSTRACT FROM AUTHOR]

Focuses on the structure and magnetic properties of iron-cobalt (Co) alloy films produced by direct current magnetron sputtering at an oblique angle of incidence. Overview of the uniaxial magnetic anisotropy in the film plane; Effect of increasing the anisotropy field on the sputtering gas and Co content; Surface morphology of the alloy films.

Presents a study which reported the effect of cobalt addition on the magnetic properties of Fe-Zr/Fe-Zr-N multilayered films. Characteristics of the multilayered films; Materials and methods used; Results.

The low rare-earth content α-Fe/Nd[SUB2]Fe[SUB14]B nanocomposite magnets having a high soft phase ratio) were fabricated by the rapid quenching method and evaluations were made of the crystallization behavior, microstructure, and magnetic properties in the annealing process. An investigation of the relationship between the roller surface velocity, V[SUBs], and magnetic properties showed that changes)in the crystal grain size of the α-Fe phase following annealing could be attributed to differences in the amorphous content of the as-melt-spun ribbons. As the amorphous content was increased, their crystal grain size tended to become finer and their magnetic properties tended to improve. However, it was observed that the optimum rapid quenching rate exists. The slight presence of clusters in as-melt-spun ribbons is favorable for obtaining good magnetic properties because the growth of a-Fe crystals is inhibited. The presumed reason for this inhibiting effect is that α-Fe growth occurs in a process in which clusters containing Nd expel this element. In the case of a completely amorphous state, large crystals grew easily, because they consisted of only Fe and Co in the initial stage. [ABSTRACT FROM AUTHOR]

The electromagnetic-noise suppression sheets made of Fe-Si-Al thin flakes embedded in polymer improve their noise suppressing performance appreciably in the magnetic field. We have already confirmed that the transmission characteristics of a microstrip line exhibit a high-frequency suppressing feature when a small piece of the sheet is placed on it @S. Yoshida et al., IEEE Trans. Magn. 37, 2401 (2001). In this article we found that this filtering performance is appreciably improved by a dc magnetic field. The effect becomes explicit in a field with intensity higher than a few hundred Oe and rise of the transmission loss becomes much steeper near the frequency of magnetic resonance. An example is that in the field of 1 kOe the 3 dB width of half to the peak of frequency profile of the transmission loss at resonance is reduced to less than a quarter of the one without magnetic field. This improvement brings about a new research subject to develop the high performance electromagnetic noise absorber that is expected to work under the optimized conditions in various digital electronic devices with operation frequencies up to the GHz band. [ABSTRACT FROM AUTHOR]

A NiZn ferrite film (3 mm thick) was deposited at 90 °C by the spin-spray ferrite plating from an aqueous solution onto a 50 Ω microstrip line formed on an epoxy printed circuit board (PCB). A strong magnetic loss was caused by the ferrite film in a GHz range, δP[SUBloss] reaching 67% attenuation at 3 GHz, the upper limit of our measurement. Furthermore, the reflection loss was very weak, S[SUB11] being smaller than 7%. Thus plated NiZn ferrite films hold strong promise to be actually applied to a type of thin film electromagnetic noise suppressors; the films can be directly deposited onto noise sources (semiconductor elements or electronic circuits) to attenuate conducted-electromagnetic noises in the GHz range. Because the plated NiZn ferrite film was magnetically isotropic in film plane, the noise suppressors will be isotropic, attenuating noise electromagnetic waves radiated from any directions. The NiZn ferrite film was also plated on a flat glass substrate as a standard, which exhibited natural resonance frequency of f[SUBr] = 500 MHz and initial real permeability of μ' = 50. Compared to these values, the film on the PCB had higher f[SUBr] of 850 MHz, though reduced in μ' to 40. But the spectrum of the imaginary permeability μ'' shifted to a higher frequency range. This facilitated the strong magnetic loss at the high frequencies. The higher f[SUBr] for the film on the PCB may be attributed to the undulated columnar structure of the film which was observed by scanning electron microscopy. [ABSTRACT FROM AUTHOR]

Shielded current perpendicular to the plane (CPP) spin valve heads with about 20 Gbit/in.² dimensions were fabricated and tested both quasistatically and dynamically. Dual synthetic spin valves with 2.3 mΩ µm² of resistivity change and area product (dRA) was used. Quasistatic tests were conducted to determine the current efficiency loss caused by the specific CPP head structure. Dynamic tests were performed to examine the flux efficiency of the readback process in the spin valve element, in order to confirm the calculation results which take into account the increase of effective anisotropy field caused by the circular sense current field. Output voltage of about 260 µV (peak to peak) was successfully obtained from the dynamic tests. Finite element modeling analysis of current distribution and temperature rise, together with degradation experiments with excessive sense current, was conducted to predict the maximum allowable current density in the 200 Gbit/in.² dimension, where read track width and stripe height are assumed to be 100 nm. With these results, requirements of spin valve material properties (dRA, RA) and the CPP structure was predicted. Essential issues to satisfy the requirements and possible solutions are also discussed. [ABSTRACT FROM AUTHOR]

Vapor phase epitaxial growth of InP with halide as the transport agent has been carried out in closed ampoules on earth and under microgravity. On earth, a large variation in the thickness of the InP grown layer has been observed with the change of the disposition of ampoules against a gravity field. A microgravity experiment has been conducted on board the Technologische Experimente Unter Schwerelosigkeit rocket for a period of approximately 6 min. The growth of the S-doped InP layer was confirmed. [ABSTRACT FROM AUTHOR]

Discusses a photoluminescence (PL) study made on an oxygen-containing silicon fine structure fabricated by a gas evaporation technique. Transmission electron microscope micrographs of the samples; Size of the crystalline portion; Data on the PL spectra taken from samples formed under various preparation conditions.

Presents information on a study which examined photoluminescence with sub-band-gap photon energies in fine silicon (Si) particles prepared by the gas-evaporation technique. Preparation of the specimens; Performance of photoluminescence studies; Description of a typical spectrum measured for the Si fine particles.

Nanoporous silica thin films with low dielectric constants were deposited by gas evaporation of SiO[sub 2] nanoparticles in an argon atmosphere. With increasing gas pressure during the evaporation, the dielectric constant decreases, while the porosity increases. The correlation between the dielectric constant and porosity is well modeled by a serial connection of two capacitors, one with air and the other with SiO[sub 2] as the dielectric medium. This suggests that the dielectric constant of the nanoporous silica thin film using the gas evaporation technique is more effectively lowered by forming “uniformly” distributed voids of closed gaps than those of the nanoporous silica films with pores extending from the back to front surface. Therefore, the former nanoporous silica thin film requires less porosity to obtain a low dielectric constant and is regarded as an ideal low-k material. © 2001 American Institute of Physics. [ABSTRACT FROM AUTHOR]

Investigates the diffusion of copper (Cu) into silicon (Si) through various barrier metals to find diffusion barrier materials for copper. Measurement of copper behavior in Cu/M/Si multilayers; Preservation of the multilayer structures of the Cu/Ta/Si and Cu/W/Si multilayers after annealing; Difference in the barrier properties of the transition metals.

Inserting earphones in your ear canal can be uncomfortable sometimes. In fact, many people with light and moderate hearing impediments do not wear earphones for this reason, although they know that hearing aids can greatly enhance their hearing. To solve this problem, a new system of hearing aid was developed that will make sounds sound louder in certain areas-around the subject's ears-than in other areas of the room. Three methods for the system were devised. They use: (1) interference of ultrasonic interference, (2) nonlinear principle of parametric speakers, and (3) equipment to accumulate sound reflection. For each method, studies were conducted on: the S/N ratio of output sound pressure to sounds in other areas, energy conversion efficiency, methods to cancel outside noise, effect on human health, and the size and price of the device. All three methods were found to be feasible. Units were built on a trial basis using the three above methods, and are being studied to see if they can actually be used as hearing aids. [ABSTRACT FROM AUTHOR]

A patient with hearing loss mainly in the high-frequency range can not clearly comprehend speech. Therefore, if the frequency band is compressed to a lower range, it is possible that the speech perception of such a patient can be improved. To test this possibility, the instrument described below was constructed and experimentally tested. First of all, a speech sample was divided into seven frequency bands, and the zero-crossing waves and envelopes were determined. The zero-crossing waves were converted to lower frequencies by flip-flop circuits, and they were amplitude-modulated by their respective envelopes. Frequency-compressed speech was obtained by the addition of the seven signals thus processed. Successful training of a person with normal hearing ability was conducted using this frequency-compressed speech. It was concluded that a high intelligibility can be thus obtained. We expect to employ this instrument in the treatment of patients with hearing impairments. [ABSTRACT FROM AUTHOR]

The photorefractive properties of the iron-doped Pb(Zn1/3Nb2/3)O3-PbTiO3 (PZN-PT) relaxor ferroelectric single crystals were investigated by two-beam coupling experiments. The Fe:0.01 wt %- and the Fe:0.1 wt %-doped 0.91PZN-0.09PT single crystals were grown with the flux solution method. The Extinction spectrum, the electro-opric coefficient, the light-induced absorption change, and the photoconductivity were measured in these samples. The maximum gain coefficient reached to 21 cm-1, which is about twice as large as that of undoped PZN-PT. The grating formation rate decreases with the Fe concentration. [ABSTRACT FROM AUTHOR]