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By utilizing a sharp magnetic needle made of a sintered Nd2Fe14B permanent magnet, we were able to produce a strong magnetic field of up to approximately 560 kA/m in a transmission electron microscope and succeeded in observing the magnetization reversal in a thin film of sintered Nd2Fe14B by in situ Lorentz microscopy. The increase in the magnetic field induced by the magnetic needle led to a pair of straight magnetic domain walls forming abruptly from the grain boundary. The successive nucleation in the neighboring grain started at the grain boundary adjacent to the magnetic domain wall formed first. Eventually, the magnetic domain walls in the neighboring grains connected and moved continuously and finally disappeared. [ABSTRACT FROM AUTHOR]

Thin-film-type magneto-optical spatial light modulator has been developed by combining one-dimensional magnetophotonic crystal (MPC) and micropatterned drive lines. The use of MPC is expected to be effective because the apparent Faraday effect, which is directly proportional to pixel contrast, is largely enhanced by the light localization of light in the vicinity of the magnetic defect in magnetophotonic crystal. The magnetophotonic crystal had a multilayer structure of (Ta2O5/SiO2)k/Bi: yttrium iron garnet/(SiO2/Ta2O5)k formed on a glass substrate, where k is the repetition number and one of optimization parameters in this study. The transmittance T decreased with an increase of k, while Faraday rotation θF increased, indicating that the enhancement of light modulation rate would be achieved by optimizing the figure of merit F defined by F≈T sin 2θF. At k=6, the maximum F=8.8 was obtained, which is about 20 times larger than that of single layer structure. [ABSTRACT FROM AUTHOR]

Structural, magnetic, magnetotransport, optical, and magneto-optical properties of (FePt)1-X(SiO2)X thin films in as-deposited state and after annealing were investigated. Magneto-optical properties were measured in the transversal Kerr effect (TKE) geometry. Magneto-optical spectra in nanocomposites (FePt)1-X(SiO2)X depend greatly on volume fraction of metal and annealing conditions. The TKE reaches the maximum value for compositions close to the percolation threshold X≈57% in as-deposited samples, as well as a maximum of the magnetoresistance. After annealing at 700 °C the TKE value significantly increases and the maximum of the magneto-optical response is observed at X≈70%. The magneto-optical spectra transformation after annealing is mainly due to the disorder-order phase transitions in FePt granules, changes in the mean granular size, and alloy microstructure. The TKE spectra calculated in the framework of the effective medium approximation for as-deposited samples are in good agreement with the experiment. © 2004 American Institute of Physics. [ABSTRACT FROM AUTHOR]

We magneto-optically investigate the switching properties of the grooved pixels. The switching field of the 70%-grooved pixel achieves a factor of over two reductions more than that of the 100%-grooved pixel. The switching properties of the geometric pixel arrays for the magneto-optic spatial light modulators are very sensitive to the depth of the pixel groove, and also depend on the state of individual pixel, in additions to the state of the neighbors in two-dimensional pixel arrays. Optimally grooved pixels can allow high amounts of bismuth in the iron garnet film, and actually reduce the driving current of the magneto-optic spatial light modulator due to a low switching threshold field. [ABSTRACT FROM AUTHOR]

We report characterization of ZnO thin-film transistors (TFTs) on glass substrates fabricated by pulsed laser deposition (PLD). ZnO films were characterized by X-ray diffraction (XRD), atomic force microscopy and Hall effect measurements. The XRD results showed high c-axis-oriented ZnO(0002) diffraction corresponding to the wurtzite phase. Moreover, the crystallization and the electrical properties of ZnO thin films grown at room temperature are controllable by PLD growth conditions such as oxygen gas pressure. The ZnO films are very smooth, with a root-mean-square roughness of 1 nm. From the Hall effect measurements, we have succeeded in fabricating ZnO films on glass substrates with an electron mobility of 21.7 cm/V s. By using the ZnO thin film grown by two-step PLD and a HfO high- k gate insulator, a transconductance of 24.1 mS/mm, a drain current on/off ratio of 4.4×10 and a subthreshold gate swing of 0.26 V/decade were obtained for the ZnO TFT. [ABSTRACT FROM AUTHOR]

Coupling of polarized light to thin opal films was examined to characterize their crystalline structure and diffraction processes in them. Photonic stop bands were observed in transmission (reflection) spectra and attributed to diffraction from the {111} crystallographic planes of the twinned fcc structure. Weakening and collapses of stop bands for linearly polarized light demonstrated a strong anisotropy of light propagation in the films. Reflection spectra of the films under the s-polarized light illumination highlighted an unusual behavior of light scattering. Multiple Bragg diffraction accompanied by leakage and inflow of energy to major diffraction lobes has been detected and described in detail. [ABSTRACT FROM AUTHOR]

ZnS thin films were deposited on glass and polymer substrates using a reaction between thiourea and a stable zinc complex, Zn(en)3SO4 (en: ethylenediamine) or Zn(trien)(ClO4)2 (trien: triethylenetetraamine), in alkaline media. In a weak alkaline solution, Zn(OH)2 films were formed. The deposition reactions were controlled by the supply of sulfide ions from thiourea at a suitable rate in alkaline media and by the dissociation of free-metal ions from the metal complex used, the stability of which defined the free Zn2+ concentration throughout the reaction. The ZnS films showed emission peaks at ca. 450 and 485 nm, and the transmittance decreased with decreasing wavelength of the incident light in the visible region of the spectrum. ZnO thin films were deposited by decomposition of Zn(en)3SO4 in the presence of Cu(en)2(ClO4)2 and thiourea; the copper(II) complex catalyzes this reaction. The ZnO films exhibited an emission peak at ca. 420 nm, and the absorbance was constant in the visible region of the spectrum. The scanning electron microscope images showed the formation of a fairly uniform surface with fine crystalline particles. [ABSTRACT FROM AUTHOR]

We have investigated extended electric field-vs.-current density E-J characteristics in YBCO coated IBAD tapes. The results of a Monte-Carlo study on the depinning in a random pin medium were compared with measurements. Using a low temperature scanning laser microscope, we examined the percolative behavior of the local resistive transition in the YBCO tape. It was also shown that the depinning probability, which is proportional to the dynamic resistance of the E-J curves, is scaled as a function of reduced current density with the aid of a power index. Consequently, the E-J characteristics in the tapes can be described by the combination of the two kinds of scaling laws: one is the scaling law of the depinning probability predicted in a random network and the other is the scaling law for the flux pinning force. These properties agree well with the percolation model of depinned clusters. [ABSTRACT FROM AUTHOR]

We have investigated the influence of sample width on the transport properties in YBCO thin film using 10, 120, and 1200 μm-wide bridges formed in a same c-axis oriented YBCO film deposited on a SrTiO3 substrate. We measured I–V characteristics of the bridges at various temperature, T, and magnetic field, B, perpendicular to the film surface. It has been found that the so called glass–liquid transition field, BGL, reduces as the sample width becomes narrower, while the critical temperature, Tc, and critical current density, Jc, in the glass region (B) are almost independent of the width of the bridges. The good agreement of Tc and Jc in three bridges indicates high uniformity of the bridges and that the reduction of BGL does not come from the degradation of the film. The measured width dependence of BGL can be scaled with a constant critical index as can be predicted by the percolation model at all measured temperature region from 70 to 85 K. The influence of sample width on Jc has also been discussed based on the scaling analysis. [Copyright &y& Elsevier]

Fabrication of L10-FePt thin films by using conventional thermal annealing and indirect rapid thermal annealing is studied. By using conventional thermal annealing, L10-FePt thin films are fabricated over 500° C. By using the rapid thermal annealing, it was found that the formation temperature of L10-FePt thin films decreases effectively. In addition, this method enables to prevent the grain growth due to annealing. [ABSTRACT FROM AUTHOR]

Provides information on a study which investigated the possibility of the application of one-dimensional magnetophotonic crystal film to optical isolator devices. Methods; Results; Discussion.

Structural, magnetic, magnetotransport, optical, and magneto-optical properties of (FePt)1-X(SiO2)X thin films in as-deposited state and after annealing were investigated. Magneto-optical properties were measured in the transversal Kerr effect (TKE) geometry. Magneto-optical spectra in nanocomposites (FePt)1-X(SiO2)X depend greatly on volume fraction of metal and annealing conditions. The TKE reaches the maximum value for compositions close to the percolation threshold X≈57% in as-deposited samples, as well as a maximum of the magnetoresistance. After annealing at 700 °C the TKE value significantly increases and the maximum of the magneto-optical response is observed at X≈70%. The magneto-optical spectra transformation after annealing is mainly due to the disorder-order phase transitions in FePt granules, changes in the mean granular size, and alloy microstructure. The TKE spectra calculated in the framework of the effective medium approximation for as-deposited samples are in good agreement with the experiment. © 2004 American Institute of Physics. [ABSTRACT FROM AUTHOR]

Abstract: Surface smoothing of laser crystallized polycrystalline silicon (poly-Si) films using gas cluster ion beam (GCIB) technology has been studied. It is found that both SF6-GCIB and O2-GCIB decrease the height of hillocks and reduce the surface roughness of the irradiated films. The mean surface roughness value of poly-Si films was reduced from 10.8nm to 2.8nm by SF6-GCIB irradiation at 80°. Ultraviolet reflectance measurement reveals that GCIB irradiation causes damage near-surface of the poly-Si films. Formation of the damage, however, can be suppressed by using GCIB irradiation at high incident angle. Effect of GCIB irradiation in a metal–insulator–semiconductor (MIS) capacitor has also been investigated. The capacitance–voltage curves of MIS capacitor with SF6-GCIB irradiation are distorted. On the contrary, the distortion is reduced by O2-GCIB irradiation at 80, which suggests that electrical-activated damage of the films can be decreased by using O2-GCIB irradiation. [Copyright &y& Elsevier]

The magnetorefractive effect in a one-dimensional magnetophotonic crystal, more specifically, a photonic crystal (SiO2/Ta2O5) containing a built-in defect in the form of a thin layer of the Co-(Al-O) magnetic nanocomposite, is studied in a computer simulation experiment. The structure of the unit cell of the photonic crystal in which most of the field energy is concentrated in cells nearest to the defect is determined. This makes it possible to increase the defect-mode Q factor and, owing to the multiple passage of light along the defect, to enhance the magnetorefractive effect by more than one order of magnitude as compared to a thin film on a substrate and by two orders of magnitude as compared to thick films. The reflectance of these structures in an applied magnetic field can be as high as 60%. [ABSTRACT FROM AUTHOR]

Abstract: A large enhancement of the Faraday rotation, which is associated with localized surface plasmon resonance (LSPR), was obtained in a sample with Au nanoparticles embedded in a Bi-substituted yttrium iron garnet (Bi:YIG) film. On a quartz substrate, Au nanoparticles were formed by heating an Au thin film, and a Bi:YIG film was then deposited on them. A sample containing the Au nanoparticles produced by 1000°C heating showed a resonant attenuation with narrower bandwidth in the transmission spectrum than nanoparticles of other samples formed by low-temperature heating. The sharp resonant Faraday rotation angle was 4.4 times larger than the estimated intrinsic Bi:YIG film at the LSPR wavelength; the angular difference was 0.14°. A discrepancy in the bandwidth between the transmission attenuation and the resonant Faraday rotation is discussed. [Copyright &y& Elsevier]

Abstract: Local anodization on a permalloy ( thin film by an atomic force microscope (AFM) in air was studied. Fabrication of uniform structure on the permalloy film was difficult in comparison with that on a Si(100) substrate. On the permalloy film, threshold voltage for the AFM anodization increased until 3h after exposure to air. With passage of time, curves on the permalloy film also changed from metallic behavior to insulating one. In addition, curves varied at positions on the permalloy film. The oxide layer with time- and position-dependencies can induce non-uniform structure in AFM anodization. However, uniformity of structure was able to be improved by using method of fabrication of dots. [Copyright &y& Elsevier]