Browsing by Author "Trypiniotis, Theodossis"

Now showing items 1-20 of 34

    • Article  

      Antivortex domain walls observed in permalloy rings via magnetic force microscopy 

      Roy, P. E.; Lee, J. H.; Trypiniotis, Theodossis; Anderson, D.; Jones, G. A. C.; Tse, D.; Barnes, C. H. W. (2009)
      Magnetic domain walls in patterned permalloy ring elements of different widths and thicknesses have been probed by magnetic force microscopy and micromagnetic simulations. We report the experimental observation of antivortex ...
    • Article  

      Digital magnetic tagging for multiplexed suspension-based biochemical assays 

      Mitrelias, Thanos; Trypiniotis, Theodossis; Palfreyman, J. J.; Hong, B.; Vyas, K.; Hayward, T. J.; Llandro, J.; Kopper, K. P.; Bland, J. A. C.; Robertson, P. A.; Barnes, C. H. W. (2009)
      Microarrays and suspension (or bead)-based technologies have attracted significant interest for their broad applications in high throughput molecular biology. However, the throughput of microarrays will always be limited ...
    • Article  

      Direct conversion of light-polarization information into electric voltage using photoinduced inverse spin-Hall effect in Pt/GaAs hybrid structure: Spin photodetector 

      Ando, K.; Morikawa, M.; Trypiniotis, Theodossis; Fujikawa, Y.; Barnes, C. H. W.; Saitoh, E. (2010)
      The direct conversion of light-polarization information into electric voltage has been demonstrated using the photoinduced inverse spin-Hall effect in a Pt/GaAs hybrid structure. In the GaAs layer, spin-polarized carriers ...
    • Article  

      Efficient spin detection across the hybrid Co/GaAs schottky interface 

      Trypiniotis, Theodossis; Tse, D. H. Y.; Steinmuller, S. J.; Cho, W. S.; Bland, J. A. C. (2007)
      The electron spin detection efficiency was studied across Co/GaAs structures using photoexcitation techniques. Two sets of samples were prepared where the substrate surface was pretreated by annealing prior to growth for ...
    • Article  

      Electric control of the spin Hall effect by intervalley transitions 

      Okamoto, N.; Kurebayashi, H.; Trypiniotis, Theodossis; Farrer, I.; Ritchie, D. A.; Saitoh, E.; Sinova, J.; Mašek, J.; Jungwirth, T.; Barnes, C. H. W. (2014)
      Controlling spin-related material properties by electronic means is a key step towards future spintronic technologies. The spin Hall effect (SHE) has become increasingly important for generating, detecting and using spin ...
    • Article  

      Electrical determination of the spin relaxation time of photoexcited electrons in GaAs 

      Kurebayashi, H.; Trypiniotis, Theodossis; Lee, K.; Easton, S.; Ionescu, A.; Farrer, I.; Ritchie, D. A.; Bland, J. A. C.; Barnes, C. H. W. (2010)
      Spin-dependent transport for photoexcited electrons in an epitaxial Fe/GaAs interface was characterized from 5 to 300 K. The presence of spin-dependent transport was confirmed at all the measured temperatures and the spin ...
    • Article  

      Electrically tunable spin injector free from the impedance mismatch problem 

      Ando, K.; Takahashi, S.; Ieda, J.; Kurebayashi, H.; Trypiniotis, Theodossis; Barnes, C. H. W.; Maekawa, S.; Saitoh, E. (2011)
      Injection of spin currents into solids is crucial for exploring spin physics and spintronics. There has been significant progress in recent years in spin injection into high-resistivity materials, for example, semiconductors ...
    • Article  

      Electron spin filtering in ferromagnet/semiconductor heterostructures 

      Bland, J. A. C.; Steinmuller, S. J.; Hirohata, A.; Cho, W. S.; Xu, Y. B.; Guertler, C. M.; Wastlbauer, G.; Ionescu, A.; Trypiniotis, Theodossis; Holmes, S. N. (2003)
      Circularly polarized light was used to generate spin-polarized electrons at room temperature in ferromagnet (FM)/GaAs Schottky diode structures. A change in the helicity-dependent photocurrent was obtained when the ...
    • Conference Object  

      High throughput biological analysis using multi-bit magnetic digital planar tags 

      Hong, B.; Jeong, J. -R; Llandro, J.; Hayward, T. J.; Ionescu, A.; Trypiniotis, Theodossis; Mitrelias, Thanos; Kopper, K. P.; Steinmuller, S. J.; Bland, J. A. C. (2008)
      We report a new magnetic labelling technology for high-throughput biomolecular identification and DNA sequencing. Planar multi-bit magnetic tags have been designed and fabricated, which comprise a magnetic barcode formed ...
    • Article  

      Highly efficient spin filtering of ballistic electrons 

      Steinmuller, S. J.; Trypiniotis, Theodossis; Cho, W. S.; Hirohata, A.; Lew, W. S.; Vaz, C. A. F.; Bland, J. A. C. (2004)
      Spin dependent electron transport in hybrid Au/Co/Cu/NiFe/n-GaAs spin valve Schottky barrier structures was investigated using photoexcitation at various wavelengths. For excitation with the photon energy well above the ...
    • Conference Object  

      Highly efficient spin filtering of ballistic electrons in hybrid spin valve/semiconductor structures 

      Steinmuller, S. J.; Trypiniotis, Theodossis; Hirohata, A.; Cho, W. S.; Lew, W. S.; Vaz, C. A. F.; Bland, J. A. C. (2004)
      The highly efficient spin filtering of ballistic electrons in hybrid spin valve/semiconductor (SC) structures was discussed. It was found that the photocurrent was dependent on the relative alignment of the light helicity ...
    • Article  

      Initial/final state selection of the spin polarization in electron tunneling across an epitaxial FeGaAs (001) interface 

      Kurebayashi, H.; Steinmuller, S. J.; Laloë, J. B.; Trypiniotis, Theodossis; Easton, S.; Ionescu, A.; Yates, J. R.; Bland, J. A. C. (2007)
      Spin dependent electron transport across epitaxial FeGaAs (001) interfaces has been investigated using photoexcitation techniques. Spin filtering is observed in the forward bias regime and its sign is switched by using ...
    • Article  

      Localized magnetic fields in arbitrary directions using patterned nanomagnets 

      McNeil, R. P. G.; Schneble, R. J.; Kataoka, M.; Ford, C. J. B.; Kasama, T.; Dunin-Borkowski, R. E.; Feinberg, J. M.; Harrison, R. J.; Barnes, C. H. W.; Tse, D. H. Y.; Trypiniotis, Theodossis; Bland, J. A. C.; Anderson, D.; Jones, G. A. C.; Pepper, M. (2010)
      Control of the local magnetic fields desirable for spintronics and quantum information technology is not well developed. Existing methods produce either moderately small local fields or one field orientation. We present ...
    • Article  

      Magnetic and structural properties of stoichiometric thin Fe 3Si/GaAs(0 0 1) films 

      Ionescu, A.; Vaz, C. A. F.; Trypiniotis, Theodossis; Gürtler, C. M.; Vickers, M. E.; García-Miquel, H.; Bland, J. A. C. (2005)
      In this study, we report experimental results on the structural and magnetic properties of epitaxial Fe3Si films grown on GaAs(0 0 1) by co-evaporation. X-ray reflectivity shows that relatively smooth interfaces are obtained ...
    • Conference Object  

      Magnetic domain-wall racetrack memory for high density and fast data storage 

      Zhao, W. S.; Zhang, Y.; Trinh, H. -P; Klein, J. -O; Chappert, C.; Mantovan, R.; Lamperti, A.; Cowburn, R. P.; Trypiniotis, Theodossis; Klaui, M.; Heinen, J.; Ocker, B.; Ravelosona, D. (2012)
      The racetrack memory device is a new concept of Magnetic RAM (MRAM) based on controlling domain wall (DW) motion in ferromagnetic nanowires. It promises ultra-high storage density thanks to the possibility to store multiple ...
    • Conference Object  

      Magnetic microtags and magnetic encoding for applications in biotechnology 

      Mitrelias, Thanos; Trypiniotis, Theodossis; Van Belle, F.; Kopper, K. P.; Steinmuller, S. J.; Anthony, J.; Bland, C.; Robertson, P. A. (2008)
      Microarrays and suspension-based technologies have attracted significant interest recently due to their broad range of applications in medical diagnostics and high throughput molecular biology. The throughput of microarrays ...
    • Article  

      Magnetic properties of Fe/AlO x/GaAs(001) structures 

      Vaz, C. A. F.; Ionescu, A.; Trypiniotis, Theodossis; Bland, J. A. C.; Dalgliesh, R. M.; Langridge, S. (2005)
      We report results on the effect of the Al Ox barrier layer on the magnetic moment of Fe using polarized neutron reflection. The sample has nominal composition 25 nm Au5 nm Fe1.3 nm Al Ox GaAs (001). The metal deposition ...
    • Article  

      Micromagnetic simulations of spin-wave normal modes and the resonant field-driven magnetization dynamics of a 360° domain wall in a soft magnetic stripe 

      Roy, P. E.; Trypiniotis, Theodossis; Barnes, C. H. W. (2010)
      Spin normal modes of a 360° domain wall trapped in a stripe are investigated by micromagnetic simulations, for two in-plane field excitation directions. Within the substructure of the 360° domain wall, we identify highly ...
    • Article  

      Novel multibit magnetic tagging techniques for high-throughput multiplexed chemical analysis 

      Hong, B.; Llandro, J.; Hayward, T. J.; Mitrelias, Thanos; Kopper, K. P.; Trypiniotis, Theodossis; Steinmuller, S. J.; Barnes, C. H. W.; Van Phong, L.; Kim, C.; Jeong, J. -R (2009)
      In this paper, we have investigated a remote encoding/decoding method of micrometer-sized multibit magnetic tags and demonstrated the operation of magnetic digital tags to discuss the practical issues which arise. The tags ...
    • Article  

      Numerical calculation model for spin-dependent transport of photoexcited electrons across Fe/GaAs(0 0 1) interfaces 

      Kurebayashi, H.; Trypiniotis, Theodossis; Lee, K.; Moutafis, C.; Easton, S.; Ionescu, A.; Bland, J. A. C.; Barnes, C. H. W. (2010)
      abs Spin-dependent transport of photogenerated electrons across Fe/GaAs(0 0 1) interfaces is calculated using a one-dimensional electron transport model. Creation of spin-polarized electrons by photoexcitation in this model ...