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Spin Injection (spin + injection)

Distribution by Scientific Domains

Physics and Astronomy	91%

Selected Abstracts

Energy Level Alignment and Interactions at Potential Contacts for Spin Injection into Organic Semiconductors,

ADVANCED ENGINEERING MATERIALS, Issue 4 2009
Mandy Grobosch
The present study provides the interface electronic properties between La0.7Sr0.3MnO3 and two archetype organic semiconductors, CuPc and , -6T using a combined X-ray- and ultraviolet photoelectron spectroscopy. La0.7Sr0.3MnO3 is a ferromagnetic metal and can be used to inject spin-polarized current into organic semiconductors. The energy level alignment depends on the cleaning procedure that is applied to the La0.7Sr0.3MnO3 surface prior to deposition of the organic semiconductor. [source]

Magnetotransport of lateral Py/Pt/Py spin valve device

PHYSICA STATUS SOLIDI (B) BASIC SOLID STATE PHYSICS, Issue 12 2007
Giju Han
Abstract Spin injection and accumulation have been investigated for Py/Pt/Py lateral spin valves with various channel length. Clear spin valve effects were found at antiparallel magnetic configuration of two ferromagnetic electrodes. The observation of memory effect suggests the spin valve effect observed in Pt channel is resulted from effective spin injection and detection. The magnitude of spin valve signal decreases as the channel length increases. The measurement yields that spin diffusion length and spin injection polarization of Pt channel is 120 nm and 18% at 5K. (© 2007 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]

Magneto-optical spectroscopy of spin injection and spin relaxation in ZnMnSe/ZnCdSe and GaMnN/InGaN spin light-emitting structures

PHYSICA STATUS SOLIDI (A) APPLICATIONS AND MATERIALS SCIENCE, Issue 1 2007
I. A. Buyanova
Abstract In this paper we review our recent results from in-depth investigations of physical mechanisms which govern efficiency of several processes important for future spintronic devises, such as spin alignment within diluted magnetic semiconductors (DMS), spin injection from DMS to non-magnetic spin detectors (SDs) and also spin depolarization within SD. Spin-injection structures based on II,VIs (e.g. ZnMnSe/Zn(Cd)Se) and III,Vs (e.g. GaMnN/Ga(In)N) were studied as model cases. Exciton spin relaxation within ZnMnSe DMS, important for spin alignment, was found to critically depend on Zeeman splitting of the exciton states and is largely facilitated by involvement of longitudinal optical (LO) phonons. Optical spin injection in ZnMnSe/Zn(Cd)Se was shown to be governed by (i) commonly believed tunneling of individual carriers or excitons and (ii) energy transfer via localized excitons and spatially separated localized electron,hole pairs (LEHP) located within DMS. Unexpectedly, the latter mechanism is in fact found to dominate spin injections. We shall also show that spin depolarization in the studied structures is essentially determined by ef- ficient spin relaxation within non-magnetic spin detectors, which is an important factor limiting efficiency of spin detection. Detailed physical mechanisms leading to efficient spin depolarization will be discussed. (© 2007 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]

Alignment of the energy levels and charge injection barriers at interfaces for spin injection: La0.7Sr0.3MnO3 in contact with organic semiconductors

PHYSICA STATUS SOLIDI (B) BASIC SOLID STATE PHYSICS, Issue 5 2008
M. Grobosch
Abstract For determination of the energy-level alignment at inter- faces between La0.7Sr0.3MnO3 films and two typical organic semiconductors, copper-phthalocyanine (CuPc) and ,-sexithiophene (,-6T) we have performed a combined X-ray and ultraviolet photoemission study. La0.7Sr0.3MnO3 thin films were grown by using the pulsed laser deposition (PLD) technique and subsequently ex-situ cleaned before the organic materials were thermally evaporated. We show that under these conditions the interfaces are free from chemical interaction and are characterized by a short-range interface dipole and large injection barriers. (© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]

Magnetotransport of lateral Py/Pt/Py spin valve device

Electrical spin injection into InGaAs quantum dots: single dot devices and time-resolved studies

PHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue 2 2009
M. Hetterich
Abstract In the context of a potential future quantum information processing we investigate the concurrent initialization of electronic spin states in InGaAs quantum dots (QDs) via electrical injection from ZnMn(S)Se spin aligners. Single dots can be read out optically through metallic apertures on top of our spin-injection light-emitting diodes (spin-LEDs). A reproducible spin polarization degree close to 100% is observed for a subset of the QD ensemble. However, the average polarization degree is lower and drops with increasing QD emission wavelength. Our measurements suggest that spin relaxation processes outside the QDs, related to the energetic position of the electron quasi-Fermi level, as well as defect-related spin scattering at the III,V/II,VI interface should be responsible for this effect, leading us to an improved device design. Finally, we present first time-resolved electroluminescence measurements of the polarization dynamics using nanosecond-pulsed electrical excitation. The latter should enable us to gain a more detailed understanding of the spin relaxation processes in our devices. They are also the first step towards future time-resolved spin manipulation experiments. (© 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]

Branching-induced spin polarization amplification in nonmagnetic semiconductors

PHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue 12 2006
S.-W. Jung
Abstract We study the spin injection in ferromagnet-tunnel barrier-semiconductor heterojunction structure embedded in the current-branching scheme. The current branching enables one to separately control the charge current from the spin current. As a result, it is possible to electrically control the spin current polarization within the semiconductor. Moreover, it can be enhanced further and may reach 100% by properly tuning the branched currents. Since the proposed scheme does not require low temperature operation, it may be a useful tool to generate the high spin current polarization at room temperature. (© 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]

Exciton dynamics in quantum nano-structures of II,VI diluted magnetic semiconductors fabricated by electron-beam lithography

PHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue 4 2004
A. Uetake
Abstract Exciton dynamics in quantum dots (QDs) of II,VI diluted magnetic semiconductors (DMSs) has been studied by using an electron-beam lithography technique. The peak energy of excitonic photoluminescence in the QDs shows blue shifts up to 3.5 meV toward the dot diameter of 20 nm, indicating a lateral confinement effect for the exciton. The time-dependent energy shift of the exciton due to the localization is small as 2.9 meV, which originates from the suppression of the exciton diffusion due to the finite dot structure. The coupled QDs composed of a DMS magnetic well (MW) and a non-magnetic well (NW) were sucessfully fabricated, where the exciton energy in the NW was designed to be lower than that in the MW. The spin-polarized excitons migrate from the MW to the NW in magnetic fields and the exciton spin injection is demonstrated in the coupled QDs. (© 2004 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]

Magnetic-field-induced switching of spin injectionin Zn1,xMnxTe/ZnTe double quantum wells

PHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue 4 2004
S. Shirotori
Abstract Magnetic-field-induced switching of the spin configuration and the resultant spin injection direction have been studied in a Zn1,xMnxTe/ZnTe double quantum well. The up- and down-spin excitons are injected from the Zn1,xMnxTe layers to the ZnTe well in weak magnetic fields, where both exciton energies in the Zn1,xMnxTe layer are higher than those in the ZnTe. Above the level crossing field, the down-spin exciton energy in the Zn1,xMnxTe layers becomes lower due to the giant Zeeman effect. Therefore, the up- and down-spin excitons are spatially separated in each layer and the down-spin exciton in the ZnTe layer is injected to the Zn1,xMnxTe. It means that the direction of the excitonic spin injection can be switched by the external field. The injection time increases from 12 psec to 300 psec toward the level crossing field of 2.5 T, since the spin-polarized excitons in those layers are associated and can cause reverse spin injection processes. (© 2004 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]