Research
Field of Specialization:
  • Magnetic Materials, Magnetic Thin Films, Multilayers
  • Diluted Magnetic Semiconductors, III-V Semiconductor Superlattices
  • Magnetic Analyses using X-ray, Spin Alignment Simulation
  • Patterned Nano-structures
Research Subjects:
  1. Study of Magnetic Properties by means of X-ray Magnetic Dichroism and/or X-ray Magnetic Scattering Method
  2. Nano-structures and Magnetism of Rare-Earth/Transition-Metal Hybrid Multilayers.
  3. Spin Orientations and Electro-Optical Properties in Rare-Earth Doped Diluted Magnetic Semiconductors.
  4. Fabrication and Characterization of Nano-scaled Patterned Structures

Fig. 1 Cross-sectional TEM iamges of magnetic semiconductor GaAsGd/GaAs suplerlattices. In high-resolution image of the right-bottom picture, we can recognize alignment of atoms. Some dislacations along <1 1 1> are also found which is distinctive for GaAs.

Fig. 2 MBE system that are used for growth of samples. With the system, we can grow III-V semiconductors, and metallic thin films of rare-earths and transition-metals. For deposition of rare-earths we use the K-cell desined for high temperature depositon.


Fig. 3 We check the crystallinity of samples by in-situ observation using RHEED(Reflection High-Energy Electron Diffraction). You can see a movie of RHEED pattern. Pattern is moving toward left which is caused by rotation of the substrate during growth. The intensity of diffraction and Kikuchi lines increases when the direction of incident beam and the high-symmetric crystal axis become parallel.
Experimental Technique (Methods and Tools):
  1. Growth of Semiconductors Superlattices, Diluted Magnetic Semiconductors, Magnetic Multilayers
    • Molecular Beam Epitaxy(MBE) method under Ultra-high Vacuum
    • Sputtering Deposition, Electron-Beam Deposition
  2. Growth of Alloys and Compounds, and Single Crystals
    • Metal-Melting method using RF-Plasma, and Arc-Plasma
    • Treatment of Cold Plasma under Atmosphere Pressure
    • Annealling under vacuum in quartz ample
  3. Measurements of Magnetic properties, Electronic properties
    • Vibrating Sample Magnetometer(VSM), Alternating Gradient Magnetometer(AGM)
    • SQUID, MPMS
    • Computer simulation of spin alignments (MSEG)
  4. Microscopic Analyses
    • Transparent Electron Microscopy(TEM), Scanning Electron Microscopy(SEM), Element-specific Image Mapping using Energy Dispersive Spectroscopy(EDS)
    • Scanning Probe Microscopies (AFM, STM, MFM)
  5. Structural Analyses using X-ray
    • High-resolution X-ray Diffraction(HR-XRD), X-ray Reflectivity(XR)
    • Scattering Simulations of Superlattice (XD)
    • X-ray Photoelectron Spectroscopy(XPS)
  6. Measurements using Synchrotron Radiation
    • Structural Analyses: EXAFS, XAS, XRD
    • Magnetic Analyses: MCD, Magnetic Diffcation, Magnetic Compton Scattering





Fig. 4 (Left-top) Deposition Source in MBE chamber.
(Left-bottom) Growth-control by PC monitoring.
(Right) MBE chamber is cooled down by flowing liquid nitrogen.
Publications:
  1. Fabrication of Transparent Antifouling Thin Films with Fractal Structure by Atmospheric Pressure Cold Plasma Deposition, Langmuir 28 (2012) pp 17761
  2. Fabrication of Al doped ZnO films using atmospheric pressure cold plasma, Thin Solid Films 522 (2012) 324
  3. Molecular vibrational dynamics in polyvinyl alcohol studied by femtosecond coherent Anti-Stokes Raman spectroscopy, Chem. Phys. Lett. 553 (2012) 26
  4. Magnetization Dynamics in Vortex-Imprinted Ni80Fe20/Ir20Mn80 Square Elements, IEEE Magnetic Letters 3 (2012) 3500204
  5. Structure and magnetic hysteresis of Gd/Fe multilayers patterned into periodic line patterns, Trans. Mater. Res. Soc. Jpn 37 (2012) 197
  6. Electrical and Optical Properties of GaNAs/GaAs MQW p-i-n Junctions, Trans. Mater. Res. Soc. Jpn 37 (2012) 193
  7. Fracture Behavior Transition by change of Strain Rate in Dislocation-induced Si Steels, Materials Science Forum 706-709 (2012) pp 2187
  8. Measurement of a Pauli and Orbital Paramagnetic State in Bulk Gold Using X-Ray Magnetic Circular Dichroism Spectroscopy, Phys Rev Lett, 108 (2012) 047201
  9. Electron Spin Resonance Observation of Bias-Temperature Stress-Induced Interface Defects at NO/N2O-Annealed Chemical-Vapor-Deposition SiO2 / (100) p-Si Substrates, Jpn. J. Appl. Phys. 50 (2011) 114101
  10. Effects of Mg doping on optical and electrical properties of GaNAs multiple quantum wells, Physica Status Solidi (c) 8 (2011) 420
  11. Incoherent interaction of propagating spin waves with precessing magnetic moments, Physical Review B, 81 (2010) 092404
  12. Formation and uniformity of double circular erosion patterns on SiO2 dielectric target in radio freqencty magnetron sputtering, J. Jpn. Soc. Precision Eng. 76, 2 (2010) 178
  13. Dependence of Al concentration on Al Doped ZnO Films Prepared by Using Atmospheric Pressure Cold Plasma, Frontier of Applied Plasma Technology, 3, 1, (2010) pp.23
  14. Enhancement and suppression of THz emission by Fabry-Perot cavity structure with a nonlinear optical crystal, Applied Optics, 48, 36 (2009) 6934
  15. Double circular erosion patterns on dielectric target in magnetron sputtering, Review of Scientific Instruments 80 (2009) 104704
  16. Structure and magnetic properties of Gd/Fe layers grown by MBE, J. Crystal Growth 311 (2009) 2143
  17. The effects of GaAs interval layer on GaNAs/GaAs superlattice structure grown by RF-MBE using modulated N radical beam sequence, Physica Status Solidi (c)5 (2008) 2750
  18. MBE Growth of Diluted Magnetic Semiconductor Gadolinium-doped GaAs, Trans. Mater. Res. Soc. Jpn 33 (2008) 299
  19. Optimization of Well Width and N Content for Optical Properties of GaNAs/GaAs Multiple Quantum Well Grown by RF-Molecular Beam Epitaxy, Jpn. J. Appl. Phys. 47 (2008) 2991
  20. Slow dephasing and local field effects of exciton-biexciton transition in β-ZnP2 detected by femtosecond degenerate four-wave mixing, J. Luminescence 124 (2007) 321
  21. Structural and optical studies of (AlAs)m/(GaAs)n type-I ultra short-period superlattices with fractional monolayer, J. Crystal Growth 301 (2007) 168
  22. GaNAs/GaAs multiple quantum well grown by modulated N radical beam sequence of RF-MBE: Effect of growth interruption, J. Crystal Growth 301 (2007) 583
  23. Transmission Spectra of Terahertz Region Hybrid One-Dimensional Photonic Crystals, AIP conf. proc. 902 (2007) 79
  24. Development of an Ultra-Thin 100 μm Diametrical Coaxial Cable using a Coating Technique, Proc. 11th Int. Conf. Precision Engineering (2006) 339
  25. Growth of GaNAs/GaAs multiple quantum well by molecular beam epitaxy using modulated N radical beam source, Jpn. J. Appl. Phys. 45 (2006) 3540
  26. Ultrafast exciton dynamics in (AlAs)0.3/(GaAs)0.7 ultrashort-period superlattice, Jpn. J. Appl. Phys. 45 (2006) 3652
  27. Structural Analyses of Fractional Monolayer (GaAs)m/(AlAs)n Superlattices by X-ray Resonant/Off-Resonant Scattering, J. Appl. Phys. 45 (2006) 3548
  28. Hard X-ray Photoelectron Emission Microscopy as Tool for Studying Buried Layers, Jpn. J. Appl. Phys. 45 (2006) 1886
  29. Depth profile of spin and orbital magnetic moments in a subnanometer Pt film on Co, Phys. Rev. B 72 (2005) 054430
  30. 100μm-Diametrical Thin Coaxial Cable for Elecctronics and Mechatronics in Upcoming Information Society, Proc. 2004 Int. Sympo. Micro-NanoMechatronics Human Sci. Jpn, (2004) 109
  31. Direct Observation of Ferromagnetic Spin Polarization in Gold Nanoparticles, Phys. Rev. Lett. 93 (2004) 116801
  32. Temperature Dependence of X-ray Magnetic Circular Dichroism in Rare Earth Iron Garnets (Rare Earth = Gd, Dy and Sm), Physica Scripta T115 (2004) 616
  33. X-ray magnetic circular dichroism study of gold nanoparticles protected by polymer, J. Magn. Magn. Mater. 272 (2004) e1183
  34. Temperature Dependence of the Rare-Earth Sublattice Magnetic Moments in R3Fe5O12 (R=Sm, Gd, and Dy） investigated by X-ray Magnetic Circular Dichroism, Tran. Mater. Res. Soc. Jpn, 29 (2004) 1501
  35. Lifetime-broadening-suppressed/free XANES spectroscopy by high-resolution resonant inelastic x-ray scattering, Phys. Rev. B 68 (2003) 045122
  36. Magnetic Compton profiles of DyCo4B and DyCo3B2, J. Phys. IV France 104 (2003) 503
  37. Orbital and spin moments in SmFe2 studied by means of white-x-ray magnetic diffraction, J. Phys. Condens. Matter, 14 (2002) 9525
  38. Temperature Dependence of Magnetic Compoton Profile in DyCo5, Material Research Society Symp. Proc. 658 (2000) GG5.10
  39. X-ray Magnetic Bragg Scattering of SmFe2, Jpn. J. Appl. Phys. 38 (1999) Suppl. 38-1, 440
and more.




Miyagawa lab, AMS, Facl.Eng., Kagawa Univ.
2217-20 Hayashi-cho, Takamatsu, JAPAN