Browsing by Author "Barnes, C. H. W."

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

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

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

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 ...

Article

Photoinduced inverse spin-Hall effect: Conversion of light-polarization information into electric voltage

Ando, K.; Morikawa, M.; Trypiniotis, Theodossis; Fujikawa, Y.; Barnes, C. H. W.; Saitoh, E. (2010)

The photoinduced inverse spin-Hall effect was observed in a Pt/GaAs hybrid structure. In the GaAs layer, circularly polarized light generates spin-polarized carriers, inducing a pure spin current into the Pt layer through ...

Article

Spin current depolarization under high electric fields in undoped InGaAs

Okamoto, N.; Kurebayashi, H.; Harii, K.; Kajiwara, Y.; Beere, H.; Farrer, I.; Trypiniotis, Theodossis; Ando, K.; Ritchie, D. A.; Barnes, C. H. W.; Saitoh, E. (2011)

Carrier spin polarization in In0.13Ga0.87 As under high electric fields has been investigated. The spin polarization was created by optical spin orientation techniques and the inverse spin-Hall effect was employed to measure ...

Article

Spin polarization control through resonant states in an Fe/GaAs Schottky barrier

Honda, S.; Itoh, H.; Inoue, J.; Kurebayashi, H.; Trypiniotis, Theodossis; Barnes, C. H. W.; Hirohata, A.; Bland, J. A. C. (2008)

Spin polarization of the tunnel conductivity has been studied for Fe/GaAs junctions with Schottky barriers. It is shown that band matching of resonant interface states within the Schottky barrier defines the sign of spin ...

Article

Spin transport in germanium at room temperature

Shen, C.; Trypiniotis, Theodossis; Lee, K. Y.; Holmes, S. N.; Mansell, R.; Husain, M.; Shah, V.; Li, X. V.; Kurebayashi, H.; Farrer, I.; De Groot, C. H.; Leadley, D. R.; Bell, G.; Parker, E. H. C.; Whall, T.; Ritchie, D. A.; Barnes, C. H. W. (2010)

Spin-dependent transport is investigated in a Ni/Ge/AlGaAs junction with an electrodeposited Ni contact. Spin-polarized electrons are excited by optical spin orientation and are subsequently used to measure the spin dependent ...

Article

Static and dynamic magnetic properties of Ni80 Fe20 square antidot arrays

Tse, D. H. Y.; Steinmuller, S. J.; Trypiniotis, Theodossis; Anderson, D.; Jones, G. A. C.; Bland, J. A. C.; Barnes, C. H. W. (2009)

We have investigated both static and dynamic magnetic properties of square antidot arrays in a ferromagnetic thin-film structure of Au (2 nm)/ Ni80 Fe20 (27.6 nm) on a SiO2 500 nm/Si substrate using magneto-optic Kerr ...

Article

Topological-charge-driven reversal of ferromagnetic rings via 360 â^~ domain-wall formation

Oyarce, A. L. G.; Trypiniotis, Theodossis; Roy, P. E.; Barnes, C. H. W. (2013)

We study the reversal mechanism between opposite closed flux states of ferromagnetic nanorings driven by an azimuthal magnetic field. The reversal proceeds via the formation of 360â^~ domain walls, and we show that the ...

Conference Object

Towards magnetic suspension assay technology

Hayward, T. J.; Llandro, J.; Kopper, K. P.; Trypiniotis, Theodossis; Mitrelias, Thanos; Bland, J. A. C.; Barnes, C. H. W. (2008)

In this study micromagnetic simulations are used to evaluate two novel approaches of magnetically tagging biomolecules in high-throughput biological assays. Comparisons are made between a simple magnetic moment-based tagging ...