Epitaxially grown MnAs∕GaAs lateral spin valves

Saha, D.; Holub, M.; Bhattacharya, P.; Liao, Y. C.

doi:10.1063/1.2358944

Cited by 52 publications

(51 citation statements)

References 22 publications

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“…24 The mesa diameter varies from 10 to 30 m and for a 10 m diameter device, the average distance traveled by the injected spin-polarized electrons is ϳ4 m. The injected spin polarization at the 25 nm MnAs/15 nm Al 0.1 Ga 0.9 As contact is 32%, determined from independent measurements on lateral GaAs spin valves. 25 The spin polarization in the active region at or near lasing threshold is FIG. 4.…”

Section: Experimental Results: Characteristics Of Quantum Dot Spimentioning

confidence: 99%

High-frequency dynamics of spin-polarized carriers and photons in a laser

2010

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The high-frequency dynamics of spin-polarized carriers and photons in a spin laser have been studied. The transient response of the device obtained from the rate equations is characterized by two sets of relaxation oscillations in the carrier and photon distributions corresponding to the two polarization modes. Consequently two distinct resonant peaks are observed in the small-signal modulation response. The calculated transient characteristics indicate that the best results are obtained from a spin laser when only the favored polarization mode, with lower threshold, is operational. Under this condition the small-signal modulation bandwidth is higher than that in a conventional laser, the threshold current is lower and the output polarization can be 100% with appropriate bias conditions, independent of the spin polarization of carriers in the active region. Measurements were made at 230 K on a InAs/GaAs quantum dot spin vertical cavity surface emitting laser. A time-averaged output polarization of 55% is measured with an active region spin polarization of 5 -6 %. The experimental results are in good agreement with calculated data.

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Section: Experimental Results: Characteristics Of Quantum Dot Spimentioning

confidence: 99%

High-frequency dynamics of spin-polarized carriers and photons in a laser

2010

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“…[6][7][8] Thus far, conventional approaches to realizing nanospintronic devices using FM III-V hybrids have been mostly "top-down" fabrication techniques after the epitaxy because it has been necessary to grow the epitaxial ferromagnetic and semiconducting layers by molecular beam epitaxy at an extremely low growth temperature. [2][3][4][5]9 We have demonstrated the epitaxy of ferromagnetic NiAstype MnAs nanoclusters ͑NCs͒ self-assembled on GaInAs/ InP ͑111͒B wafers by metal-organic vapor phase epitaxy ͑MOVPE͒. 10,11 For the NiAs-type ͑or ZB-type͒ MnAs growth, the ͕111͖ orientations of ZB-type layers are promising because of the similarity of their crystal structures.…”

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Magnetic domain characterizations of anisotropic-shaped MnAs nanoclusters position-controlled by selective-area metal-organic vapor phase epitaxy

Ito

Hara

Wakatsuki

et al. 2009

Applied Physics Letters

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The authors report the buildup fabrication and magnetic domain characterizations of anisotropic-shaped MnAs nanoclusters position-controlled on partially SiO 2 -masked GaAs ͑111͒B substrates by selective-area metal-organic vapor phase epitaxy. Magnetic force microscopy reveals that both the symmetric-and anisotropic-shaped nanoclusters show spontaneous magnetization at room temperature. Some of the nanoclusters show a single magnetic domain, in which magnetized directions are along one of the a-axes of NiAs-type MnAs, after the external magnetic fields up to 3500 Gauss are applied in-plane. The magnetic domains are well controlled by introducing both magnetocrystalline and shape magnetic anisotropies in the anisotropic-shaped nanoclusters. © 2009 American Institute of Physics. ͓DOI: 10.1063/1.3157275͔ Recent research activities for heteroepitaxial nanostructures of ferromagnet and III-V compound semiconductor ͑FM III-V hybrids͒ have gained much attention in the future nanospintronic device applications.1 It was reported that large tunneling magnetoresistance effect was shown in the MnAs/AlAs/MnAs heterostructures 2 and the GaAs:MnAs granular layers 3,4 above room temperature ͑RT͒, and that ferromagnetic NiAs-type MnAs layers served as an electrical spin injection source for semiconductors. 5 In recent theoretical calculations, in addition, it has been predicted that the electronic band-structure of hypothetical zinc-blende ͑ZB͒-type MnAs layers is half-metallic, which is promising nature for device applications.6-8 Thus far, conventional approaches to realizing nanospintronic devices using FM III-V hybrids have been mostly "top-down" fabrication techniques after the epitaxy because it has been necessary to grow the epitaxial ferromagnetic and semiconducting layers by molecular beam epitaxy at an extremely low growth temperature. [2][3][4][5]9

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“…One example of such a device is the lateral spin-valve (LSV), in which two ferromagnetic (FM) electrodes are connected laterally by a non-magnetic (NM) wire. The efficiency of these is dependent on the choice of materials, and also relies heavily on the quality of interfaces for efficient spin injection from a FM into a NM metal [3][4][5], semiconductor [6,7], or also superconductor [8,9]. LSVs can provide information on spin injection and accumulation at the interfaces, as well as the spin diffusion length in the NM wire.…”

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confidence: 99%