Hironaga Uchida - Profile on Academia.edu (original) (raw)
Papers by Hironaga Uchida
Journal of Magnetics, 2006
We studied local anodization on permalloy (Ni 80 Fe 20 ) thin film with an atomic force microscop... more We studied local anodization on permalloy (Ni 80 Fe 20 ) thin film with an atomic force microscope (AFM), which was performed by applying a voltage between the permalloy sample and conductive AFM tip. Comparing with anodization on Si (100) substrate, nano-structures on the permalloy thin film was fabricated with low processability. In order to improve the processability on the permalloy thin film, we used dot-fabrication method, that is, a conductive AFM probe was kept at a position on the film during the anodization process.
Time-resolved atomic-scale modification of silicon with a scanning tunneling microscope
Journal of Vacuum Science & Technology B: Microelectronics and Nanometer Structures Processing, Measurement, and Phenomena, 1994
Voltage pulses applied between the tip of a scanning tunneling microscope (STM) and a crystal sur... more Voltage pulses applied between the tip of a scanning tunneling microscope (STM) and a crystal surface often result in extraction or deposition of single atoms or clusters of atoms on the surface, which are detected by imaging the affected area with the STM after the pulse. Here, atomic-scale displacements of the STM tip during such surface modifications, due to structural changes occurring at the tunnel junction are studied. Using this technique, it is found that for the Si(111)7×7 surface and a W tip, modification during the pulse is field induced and not current induced, but that a considerable fraction of modification events occur shortly after a pulse. The ability to predict the type of modification from the direction of the tip displacement is investigated, and the applicability of this approach to high-speed nanofabrication is discussed.
MRS Proceedings, 2003
ABSTRACTA magneto-optic spatial light modulator (MOSLM) driven by electric field is presented. Us... more ABSTRACTA magneto-optic spatial light modulator (MOSLM) driven by electric field is presented. Using finite element method simulation, the parameters of the MOSLM are decided including the 1 μm piezoelectric lead zirconate titanate (PZT)-based layer, the 200 nm bottom electrode, and the 8V electrical applied voltage. A flat surface magneto-optical bismuth-substituted iron garnet (Bi:YIG) based film having an array-pixels structure was created by a site-selected epitaxial method on a SGGG-based substrate. In order to avoid high temperature annealing process which may damage the Bi:YIG film, the PZT film was deposited by the aerosol deposition method (ADM) on the Bi:YIG film. By stress field induced by the PZT film to the Bi:YIG film with an external magnetic field, the pixels of the device were successfully switched.
IEEE Transactions on Magnetics, 2014
Low-temperature preparation of a Co/Pt layer-stacked film with high-magnetic anisotropy was studi... more Low-temperature preparation of a Co/Pt layer-stacked film with high-magnetic anisotropy was studied using collimated sputter deposition. Only a trace superlattice line, corresponding to the L1 1 -ordered phase of CoPt, was observed in the X-ray diffraction pattern. However, magnetic properties, exhibited high-saturation magnetization of about 1000 emu/cm 3 and large perpendicular magnetic anisotropy, even when the film was deposited at room temperature. For room-temperature deposition, layer-stacked films deposited at a high-Ar pressure of 9.6 Pa exhibited a high coercivity of around 5 kOe and an anisotropy field of around 15 kOe, indicating a high-perpendicular anisotropy of 6.5 × 10 6 erg/cm 3 . Deposition at 200 °C increased the anisotropy field up to 20 kOe, indicating a high anisotropy of 1 × 10 7 erg/cm 3 . Films deposited without the collimator showed no superlattice line in XRD patterns and exhibited low-saturation magnetization and anisotropy. The cause of the high-perpendicular anisotropy is suggested to be micro ordering in the film.
MRS Proceedings, 2003
ABSTRACTIn a magneto-surface-acoustic-wave (MSAW) device, phase velocity is controlled by an exte... more ABSTRACTIn a magneto-surface-acoustic-wave (MSAW) device, phase velocity is controlled by an external magnetic field. We proposed amplification of MSAW with a hybrid structure of FeB amorphous film / InSb semiconductor thin film / LiNbO3 substrate, which is expected to compensate the attenuation of MSAW caused by eddy current loss. In the fabricated MSAW device having the FeB amorphous film with low coercivity and high magnetostrictive, the phase retardation of about 600 degree/cm at magnetic fields of ±300 Oe was obtained. The InSb thin film with a mobility of about 3.5×103 cm2/Vs was obtained by using annealing process. The results show possibility of the MSAW amplification.
Flat-surface magneto-optic spatial light modulator by using thermal infrared ray annealing
SPIE Proceedings, 2003
We demonstrated a flat-surface magneto-optic spatial light modulator (MOSLM) without physically i... more We demonstrated a flat-surface magneto-optic spatial light modulator (MOSLM) without physically isolated pixels and an external bias coil. The flat-surface MOSLM, which was fabricated by a simple process, was designed as a compact system with a high resolution and very low ...
Design of multimode EO waveguide for hologram optical switch
2007 Conference on Lasers and Electro-Optics - Pacific Rim, 2007
ABSTRACT The paper illustrates the structure of a multimode electro-optic ( EO ) waveguide, and w... more ABSTRACT The paper illustrates the structure of a multimode electro-optic ( EO ) waveguide, and we optimized a thickness d. The core of the multimode EO waveguide thickness d is 6 mum has a good performance to obtain the homogeneous electric field in the waveguide.
Analysis of Opal Template for Three Dimentional Magnetophotonic Crystals
INTERMAG 2006 - IEEE International Magnetics Conference, 2006
Periodic structures of dielectric materials in submicrometer are currently paid much attention as... more Periodic structures of dielectric materials in submicrometer are currently paid much attention as photonic crystals (PC) with photonic band gap (PBG), which prohibits light of specific wavelength from propagating in certain directions. We reported one-dimensional magnetophotonic crystals (1D-MPCs) constructed of dielectric multi layers and a magnetic defect layer obtained large enhancement of Faraday rotation in localized mode. On the other
Fabrication and magneto-optical responses of Au-Bi:YIG films
SPIE Proceedings, 2008
ABSTRACT We have studied magneto-optical responses of gold-bismuth-substituted yttrium iron garne... more ABSTRACT We have studied magneto-optical responses of gold-bismuth-substituted yttrium iron garnet (Au-Bi:YIG) composite films in which Au particles are embedded into Bi:YIG in two different ways. First type were samples in which planar arrays of Au particles were introduced into the middle of Bi:YIG films using a step-by-step sputtering technique. Second type were granular films fabricated using simultaneous co-sputtering of Au and Bi:YIG; in these films Au particles occupy positions inside composite films in a random way. Absorption bands associated with localized surface plasmon resonances (LSPRs) were observed in transmission spectra of films of both types. In the spectral range of LSPRs, samples of Au-array type exhibited larger Faraday rotation angles as compared with that for reference Bi:YIG films of the same thickness. However, given that the volume fraction of Au particles was nearly the same for both types, the enhancement of Faraday rotation for samples of Au-granular type was insignificantly altered. Experiments showed that of the primary importance is the role of the interfaces between Au particles and Bi:YIG. Theoretical estimations showed that, in samples of Au-granular type, air shells appeared between Au particles and Bi:YIG during fabrication. In fact, annealing needed for crystallization of Bi:YIG films is always accompanied with an expansion of their thicknesses.
Analysis of STM Images after Atom Extractions from the Si(111) 7 × 7 Unit Cell through a Cluster Model
The Journal of Physical Chemistry B, 1997
ABSTRACT Using an ab initio cluster model, we have investigated the electronic information contai... more ABSTRACT Using an ab initio cluster model, we have investigated the electronic information contained in scanning tunneling microscope (STM) images, which were obtained after atom extraction from the Si(111) 7 × 7 surface. Depending on the position of the created vacancy (corner versus center) and on the number of extracted atoms (single atom versus dimer), we obtain different density maps that permit us to propose a rationalization of the brightness of the spots that are observed in the corresponding experimental STM images. It can be understood by a localization of the surface state near the created atomic vacancy.
Surface Science, 2004
We investigated adsorption of an Al atom on the Si(1 1 1)7 • 7 surface by using a scanning tunnel... more We investigated adsorption of an Al atom on the Si(1 1 1)7 • 7 surface by using a scanning tunneling microscope. The evaporated Al atom displaced a Si center adatom of the surface; the expelled Si atom diffused inside a half unit cell of the Si(1 1 1)7 • 7 surface. The adsorbed single Al atom, which shows bias voltage dependency, hopped among three center adatom sites inside the half unit cell. Ab initio molecular orbital method was used to investigate the adsorption of Al atom on the surface.
Surface Science, 2003
We investigate adsorbed Si atoms on the Si(1 1 1)7 Â 7 surface deposited from an scanning tunneli... more We investigate adsorbed Si atoms on the Si(1 1 1)7 Â 7 surface deposited from an scanning tunneling microscope (STM) tip. In our experiments at room temperature, two types of Si adsorbates on the surface are observed, ''staying'' Si adsorbate that remains at the same position, and ''diffusing'' Si one that is detected as a noise-like feature on an STM image. Molecular orbital calculations are performed to distinguish difference of these Si adsorbates. Stable positions, transition states, diffusion barriers and electron density iso-surfaces for extra Si atoms on Si cluster models are obtained. From these results, we propose new assignments to these Si adsorbates: the staying and diffusing Si adsorbates correspond to two Si atoms and a single Si atom, respectively.
Proceedings of the Japan Academy. Ser. B: Physical and Biological Sciences, 1993
By monitoring the vertical motion of the tip of a scanning tunneling microscope (STM) during atom... more By monitoring the vertical motion of the tip of a scanning tunneling microscope (STM) during atomic manipulation on a surface, we have been able to detect for the first time Angstrom-scale displacements of the tip which are associated with the extraction and deposition of atoms on the surface, due to voltage pulses applied to the sample. The temporal distribution of these tip displacements during and after the application of the voltage pulse yields important information about the nature of the modification process.
Physical Review Letters, 1994
The Si(l 1 1)-(7X7) surface can be locally bydrized at the nanometer scale by depositing H atoms ... more The Si(l 1 1)-(7X7) surface can be locally bydrized at the nanometer scale by depositing H atoms from the tip of a scanning tunneling microscope. The H atoms to be deposited are continuously supplied to the tip made of Pt (20% lr) from an ambient Hq molecule gas through dissociative adsorption (H2 2H) and are deposited onto the Si( )-(7x7) sample surface one by one by field evaporation; although the ambient H2 molecules are not adsorbed on the Si( )-(7x7)surface, the H atoms from the tip are adsorbed on the surface.
Physical Review B, 2008
The magneto-optical Faraday effect is studied in one-dimensional magnetophotonic crystals ͑MPCs͒.... more The magneto-optical Faraday effect is studied in one-dimensional magnetophotonic crystals ͑MPCs͒. Mechanisms of a strong enhancement of the Faraday rotation at the edges of the photonic band gap are considered. High difference of refractive indexes of bismuth-substituted yttrium iron garnet ͑Bi:YIG͒ and SiO 2 layers provides a strong spatial localization of the optical field in Bi:YIG layers, which leads to manifold Faraday rotation enhancement at the photonic band edges. The Faraday rotation angle in the finite MPCs appears to be a nonlinear function of the total thickness of magnetic material in the stack that can be interpreted as the nonlinear Verdet law. Relation between the enhancement of the Faraday rotation and localization of optical field in magnetic layers is treated as a Borrmann-type effect. This relation shows that the Faraday rotation can be considered as a measure of the density of photonic states trapped within Bi:YIG layers.
LC filter-type magnetoimpedance sensors with multilayer film structure
physica status solidi (c), 2007
ABSTRACT We have investigated the basic characteristics and applicability of the LC high pass fil... more ABSTRACT We have investigated the basic characteristics and applicability of the LC high pass filter configuration for signal conditioning of the magnetoimpedance (MI) sensor. The MI sensor elements were fabricated through photolithography and lift-off process of CoZrNb/Au/CoZrNb multilayer, and the LC high pass filters were configured using the fabricated sensor elements and surface mount capacitors. To confirm the high frequency performance of the sensor elements, frequency dependence of the impedance was measured as function of external magnetic field using a network analyzer. The output increased to reach the peak value with increase of magnetic field to around 20 Oe, which was almost the same with the anisotropic field of the multilayer film pattern, and the measured maximum change ratio is 49%. (© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)
Figures of merit of magneto‐optic spatial light modulators with magnetophotonic crystals
physica status solidi c, 2007
ABSTRACT This paper presents the simulated and measured results of two types of one dimensional m... more ABSTRACT This paper presents the simulated and measured results of two types of one dimensional magnetophotonic crystals (1-D MPC) with single cavity and dual cavity respectively for applcation to thin film type magneto-optic spatial light modulators (MOSLMs). The use of MPC is expected to be effective for thin film type MOSLM, because the apparent Faraday rotation is largely enhanced due to light localization in magnetic defect layer of MPC with a large number of periodic dielectric layers. The complex chracteristics of MPCs are discussed in this paper – Faraday rotation θF, transmittance T, and figure of merit F = T sin(2θF). It is key point of finding optimal structure of MPC for application of MOSLM to use F, because the T decreased with increase of k, while Faraday rotation θF increased, indicating that the enhancement of light modulation rate could be achieved by optimizing the figure of merit F defined by F ≈ T ·sin2θF. The maximum F = 13.7 was obtained in dual cavity MPC, while F = 12.5 was obtained in single cavity MPC. (© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)
Fabrication and swimming properties of micro‐machine coated with magnetite prepared by ferrite plating
physica status solidi (b), 2004
By the sterolithography technique and the ferrite plating, we have fabricated a magnetic micro‐ma... more By the sterolithography technique and the ferrite plating, we have fabricated a magnetic micro‐machine which coated Fe3O4. The sterolithography technique enables to form the spiral‐shape resinous templates and the ferrite plating enables to coat Fe3O4 uniformly onto these templates from an aqueous solution. The total machine weight is light because a resin of the template body is almost the same density as water. We have verified that the machines swim freely and wirelessly in water by applying a rotational magnetic field. As the machine coated with Fe3O4 has a biocompatibility, there is a possibility of medical micro‐robots which swim in human body for medical operations. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Journal of Magnetism and Magnetic Materials, 2004
We demonstrated the flat-surface magneto-optic spatial light modulators (MOSLM) without the artif... more We demonstrated the flat-surface magneto-optic spatial light modulators (MOSLM) without the artificially isolation of pixels and external bias coil. The pixels of the MOSLM were switched by over ten times smaller driving current than that of the conventional MOSLM. In addition, the developed novel flat-surface MOSLM provides high resolution with low driving current without external bias coil.
Journal of Magnetics, 2006
We studied local anodization on permalloy (Ni 80 Fe 20 ) thin film with an atomic force microscop... more We studied local anodization on permalloy (Ni 80 Fe 20 ) thin film with an atomic force microscope (AFM), which was performed by applying a voltage between the permalloy sample and conductive AFM tip. Comparing with anodization on Si (100) substrate, nano-structures on the permalloy thin film was fabricated with low processability. In order to improve the processability on the permalloy thin film, we used dot-fabrication method, that is, a conductive AFM probe was kept at a position on the film during the anodization process.
Time-resolved atomic-scale modification of silicon with a scanning tunneling microscope
Journal of Vacuum Science & Technology B: Microelectronics and Nanometer Structures Processing, Measurement, and Phenomena, 1994
Voltage pulses applied between the tip of a scanning tunneling microscope (STM) and a crystal sur... more Voltage pulses applied between the tip of a scanning tunneling microscope (STM) and a crystal surface often result in extraction or deposition of single atoms or clusters of atoms on the surface, which are detected by imaging the affected area with the STM after the pulse. Here, atomic-scale displacements of the STM tip during such surface modifications, due to structural changes occurring at the tunnel junction are studied. Using this technique, it is found that for the Si(111)7×7 surface and a W tip, modification during the pulse is field induced and not current induced, but that a considerable fraction of modification events occur shortly after a pulse. The ability to predict the type of modification from the direction of the tip displacement is investigated, and the applicability of this approach to high-speed nanofabrication is discussed.
MRS Proceedings, 2003
ABSTRACTA magneto-optic spatial light modulator (MOSLM) driven by electric field is presented. Us... more ABSTRACTA magneto-optic spatial light modulator (MOSLM) driven by electric field is presented. Using finite element method simulation, the parameters of the MOSLM are decided including the 1 μm piezoelectric lead zirconate titanate (PZT)-based layer, the 200 nm bottom electrode, and the 8V electrical applied voltage. A flat surface magneto-optical bismuth-substituted iron garnet (Bi:YIG) based film having an array-pixels structure was created by a site-selected epitaxial method on a SGGG-based substrate. In order to avoid high temperature annealing process which may damage the Bi:YIG film, the PZT film was deposited by the aerosol deposition method (ADM) on the Bi:YIG film. By stress field induced by the PZT film to the Bi:YIG film with an external magnetic field, the pixels of the device were successfully switched.
IEEE Transactions on Magnetics, 2014
Low-temperature preparation of a Co/Pt layer-stacked film with high-magnetic anisotropy was studi... more Low-temperature preparation of a Co/Pt layer-stacked film with high-magnetic anisotropy was studied using collimated sputter deposition. Only a trace superlattice line, corresponding to the L1 1 -ordered phase of CoPt, was observed in the X-ray diffraction pattern. However, magnetic properties, exhibited high-saturation magnetization of about 1000 emu/cm 3 and large perpendicular magnetic anisotropy, even when the film was deposited at room temperature. For room-temperature deposition, layer-stacked films deposited at a high-Ar pressure of 9.6 Pa exhibited a high coercivity of around 5 kOe and an anisotropy field of around 15 kOe, indicating a high-perpendicular anisotropy of 6.5 × 10 6 erg/cm 3 . Deposition at 200 °C increased the anisotropy field up to 20 kOe, indicating a high anisotropy of 1 × 10 7 erg/cm 3 . Films deposited without the collimator showed no superlattice line in XRD patterns and exhibited low-saturation magnetization and anisotropy. The cause of the high-perpendicular anisotropy is suggested to be micro ordering in the film.
MRS Proceedings, 2003
ABSTRACTIn a magneto-surface-acoustic-wave (MSAW) device, phase velocity is controlled by an exte... more ABSTRACTIn a magneto-surface-acoustic-wave (MSAW) device, phase velocity is controlled by an external magnetic field. We proposed amplification of MSAW with a hybrid structure of FeB amorphous film / InSb semiconductor thin film / LiNbO3 substrate, which is expected to compensate the attenuation of MSAW caused by eddy current loss. In the fabricated MSAW device having the FeB amorphous film with low coercivity and high magnetostrictive, the phase retardation of about 600 degree/cm at magnetic fields of ±300 Oe was obtained. The InSb thin film with a mobility of about 3.5×103 cm2/Vs was obtained by using annealing process. The results show possibility of the MSAW amplification.
Flat-surface magneto-optic spatial light modulator by using thermal infrared ray annealing
SPIE Proceedings, 2003
We demonstrated a flat-surface magneto-optic spatial light modulator (MOSLM) without physically i... more We demonstrated a flat-surface magneto-optic spatial light modulator (MOSLM) without physically isolated pixels and an external bias coil. The flat-surface MOSLM, which was fabricated by a simple process, was designed as a compact system with a high resolution and very low ...
Design of multimode EO waveguide for hologram optical switch
2007 Conference on Lasers and Electro-Optics - Pacific Rim, 2007
ABSTRACT The paper illustrates the structure of a multimode electro-optic ( EO ) waveguide, and w... more ABSTRACT The paper illustrates the structure of a multimode electro-optic ( EO ) waveguide, and we optimized a thickness d. The core of the multimode EO waveguide thickness d is 6 mum has a good performance to obtain the homogeneous electric field in the waveguide.
Analysis of Opal Template for Three Dimentional Magnetophotonic Crystals
INTERMAG 2006 - IEEE International Magnetics Conference, 2006
Periodic structures of dielectric materials in submicrometer are currently paid much attention as... more Periodic structures of dielectric materials in submicrometer are currently paid much attention as photonic crystals (PC) with photonic band gap (PBG), which prohibits light of specific wavelength from propagating in certain directions. We reported one-dimensional magnetophotonic crystals (1D-MPCs) constructed of dielectric multi layers and a magnetic defect layer obtained large enhancement of Faraday rotation in localized mode. On the other
Fabrication and magneto-optical responses of Au-Bi:YIG films
SPIE Proceedings, 2008
ABSTRACT We have studied magneto-optical responses of gold-bismuth-substituted yttrium iron garne... more ABSTRACT We have studied magneto-optical responses of gold-bismuth-substituted yttrium iron garnet (Au-Bi:YIG) composite films in which Au particles are embedded into Bi:YIG in two different ways. First type were samples in which planar arrays of Au particles were introduced into the middle of Bi:YIG films using a step-by-step sputtering technique. Second type were granular films fabricated using simultaneous co-sputtering of Au and Bi:YIG; in these films Au particles occupy positions inside composite films in a random way. Absorption bands associated with localized surface plasmon resonances (LSPRs) were observed in transmission spectra of films of both types. In the spectral range of LSPRs, samples of Au-array type exhibited larger Faraday rotation angles as compared with that for reference Bi:YIG films of the same thickness. However, given that the volume fraction of Au particles was nearly the same for both types, the enhancement of Faraday rotation for samples of Au-granular type was insignificantly altered. Experiments showed that of the primary importance is the role of the interfaces between Au particles and Bi:YIG. Theoretical estimations showed that, in samples of Au-granular type, air shells appeared between Au particles and Bi:YIG during fabrication. In fact, annealing needed for crystallization of Bi:YIG films is always accompanied with an expansion of their thicknesses.
Analysis of STM Images after Atom Extractions from the Si(111) 7 × 7 Unit Cell through a Cluster Model
The Journal of Physical Chemistry B, 1997
ABSTRACT Using an ab initio cluster model, we have investigated the electronic information contai... more ABSTRACT Using an ab initio cluster model, we have investigated the electronic information contained in scanning tunneling microscope (STM) images, which were obtained after atom extraction from the Si(111) 7 × 7 surface. Depending on the position of the created vacancy (corner versus center) and on the number of extracted atoms (single atom versus dimer), we obtain different density maps that permit us to propose a rationalization of the brightness of the spots that are observed in the corresponding experimental STM images. It can be understood by a localization of the surface state near the created atomic vacancy.
Surface Science, 2004
We investigated adsorption of an Al atom on the Si(1 1 1)7 • 7 surface by using a scanning tunnel... more We investigated adsorption of an Al atom on the Si(1 1 1)7 • 7 surface by using a scanning tunneling microscope. The evaporated Al atom displaced a Si center adatom of the surface; the expelled Si atom diffused inside a half unit cell of the Si(1 1 1)7 • 7 surface. The adsorbed single Al atom, which shows bias voltage dependency, hopped among three center adatom sites inside the half unit cell. Ab initio molecular orbital method was used to investigate the adsorption of Al atom on the surface.
Surface Science, 2003
We investigate adsorbed Si atoms on the Si(1 1 1)7 Â 7 surface deposited from an scanning tunneli... more We investigate adsorbed Si atoms on the Si(1 1 1)7 Â 7 surface deposited from an scanning tunneling microscope (STM) tip. In our experiments at room temperature, two types of Si adsorbates on the surface are observed, ''staying'' Si adsorbate that remains at the same position, and ''diffusing'' Si one that is detected as a noise-like feature on an STM image. Molecular orbital calculations are performed to distinguish difference of these Si adsorbates. Stable positions, transition states, diffusion barriers and electron density iso-surfaces for extra Si atoms on Si cluster models are obtained. From these results, we propose new assignments to these Si adsorbates: the staying and diffusing Si adsorbates correspond to two Si atoms and a single Si atom, respectively.
Proceedings of the Japan Academy. Ser. B: Physical and Biological Sciences, 1993
By monitoring the vertical motion of the tip of a scanning tunneling microscope (STM) during atom... more By monitoring the vertical motion of the tip of a scanning tunneling microscope (STM) during atomic manipulation on a surface, we have been able to detect for the first time Angstrom-scale displacements of the tip which are associated with the extraction and deposition of atoms on the surface, due to voltage pulses applied to the sample. The temporal distribution of these tip displacements during and after the application of the voltage pulse yields important information about the nature of the modification process.
Physical Review Letters, 1994
The Si(l 1 1)-(7X7) surface can be locally bydrized at the nanometer scale by depositing H atoms ... more The Si(l 1 1)-(7X7) surface can be locally bydrized at the nanometer scale by depositing H atoms from the tip of a scanning tunneling microscope. The H atoms to be deposited are continuously supplied to the tip made of Pt (20% lr) from an ambient Hq molecule gas through dissociative adsorption (H2 2H) and are deposited onto the Si( )-(7x7) sample surface one by one by field evaporation; although the ambient H2 molecules are not adsorbed on the Si( )-(7x7)surface, the H atoms from the tip are adsorbed on the surface.
Physical Review B, 2008
The magneto-optical Faraday effect is studied in one-dimensional magnetophotonic crystals ͑MPCs͒.... more The magneto-optical Faraday effect is studied in one-dimensional magnetophotonic crystals ͑MPCs͒. Mechanisms of a strong enhancement of the Faraday rotation at the edges of the photonic band gap are considered. High difference of refractive indexes of bismuth-substituted yttrium iron garnet ͑Bi:YIG͒ and SiO 2 layers provides a strong spatial localization of the optical field in Bi:YIG layers, which leads to manifold Faraday rotation enhancement at the photonic band edges. The Faraday rotation angle in the finite MPCs appears to be a nonlinear function of the total thickness of magnetic material in the stack that can be interpreted as the nonlinear Verdet law. Relation between the enhancement of the Faraday rotation and localization of optical field in magnetic layers is treated as a Borrmann-type effect. This relation shows that the Faraday rotation can be considered as a measure of the density of photonic states trapped within Bi:YIG layers.
LC filter-type magnetoimpedance sensors with multilayer film structure
physica status solidi (c), 2007
ABSTRACT We have investigated the basic characteristics and applicability of the LC high pass fil... more ABSTRACT We have investigated the basic characteristics and applicability of the LC high pass filter configuration for signal conditioning of the magnetoimpedance (MI) sensor. The MI sensor elements were fabricated through photolithography and lift-off process of CoZrNb/Au/CoZrNb multilayer, and the LC high pass filters were configured using the fabricated sensor elements and surface mount capacitors. To confirm the high frequency performance of the sensor elements, frequency dependence of the impedance was measured as function of external magnetic field using a network analyzer. The output increased to reach the peak value with increase of magnetic field to around 20 Oe, which was almost the same with the anisotropic field of the multilayer film pattern, and the measured maximum change ratio is 49%. (© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)
Figures of merit of magneto‐optic spatial light modulators with magnetophotonic crystals
physica status solidi c, 2007
ABSTRACT This paper presents the simulated and measured results of two types of one dimensional m... more ABSTRACT This paper presents the simulated and measured results of two types of one dimensional magnetophotonic crystals (1-D MPC) with single cavity and dual cavity respectively for applcation to thin film type magneto-optic spatial light modulators (MOSLMs). The use of MPC is expected to be effective for thin film type MOSLM, because the apparent Faraday rotation is largely enhanced due to light localization in magnetic defect layer of MPC with a large number of periodic dielectric layers. The complex chracteristics of MPCs are discussed in this paper – Faraday rotation θF, transmittance T, and figure of merit F = T sin(2θF). It is key point of finding optimal structure of MPC for application of MOSLM to use F, because the T decreased with increase of k, while Faraday rotation θF increased, indicating that the enhancement of light modulation rate could be achieved by optimizing the figure of merit F defined by F ≈ T ·sin2θF. The maximum F = 13.7 was obtained in dual cavity MPC, while F = 12.5 was obtained in single cavity MPC. (© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)
Fabrication and swimming properties of micro‐machine coated with magnetite prepared by ferrite plating
physica status solidi (b), 2004
By the sterolithography technique and the ferrite plating, we have fabricated a magnetic micro‐ma... more By the sterolithography technique and the ferrite plating, we have fabricated a magnetic micro‐machine which coated Fe3O4. The sterolithography technique enables to form the spiral‐shape resinous templates and the ferrite plating enables to coat Fe3O4 uniformly onto these templates from an aqueous solution. The total machine weight is light because a resin of the template body is almost the same density as water. We have verified that the machines swim freely and wirelessly in water by applying a rotational magnetic field. As the machine coated with Fe3O4 has a biocompatibility, there is a possibility of medical micro‐robots which swim in human body for medical operations. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Journal of Magnetism and Magnetic Materials, 2004
We demonstrated the flat-surface magneto-optic spatial light modulators (MOSLM) without the artif... more We demonstrated the flat-surface magneto-optic spatial light modulators (MOSLM) without the artificially isolation of pixels and external bias coil. The pixels of the MOSLM were switched by over ten times smaller driving current than that of the conventional MOSLM. In addition, the developed novel flat-surface MOSLM provides high resolution with low driving current without external bias coil.