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We present a simultaneous investigation of coherent spin dynamics in both localized and itinerant carriers in Fe/GaAs heterostructures using ultrafast and spin-resolved pump-probe spectroscopy. We find that for excitation densities that…

Mesoscale and Nanoscale Physics · Physics 2018-10-31 Yu-Sheng Ou , N. J. Harmon , Patrick Odenthal , R. K. Kawakami , M. E. Flatté , E. Johnston-Halperin

The longest spin lifetimes in bulk n-GaAs exceed 100 ns for doping concentrations near the metal-insulator transition (J.M. Kikkawa, D.D. Awschalom, Phys. Rev. Lett. 80, 4313 (1998)). The respective electronic states have yet not been…

Materials Science · Physics 2007-06-14 L. Schreiber , M. Heidkamp , T. Rohleder , B. Beschoten , G. Güntherodt

We develop a theory of spin noise spectroscopy of itinerant, noninteracting, spin-carrying fermions in different regimes of temperature and disorder. We use kinetic equations for the density matrix in spin variables. We find a general…

Statistical Mechanics · Physics 2015-05-14 Simon Kos , Alexander V. Balatsky , Peter B. Littlewood , Darryl L. Smith

We propose an electrically driven spin injector into normal metals and semiconductors, which is based on a magnetic tunnel junction (MTJ) subjected to a microwave voltage. Efficient functioning of such an injector is provided by…

Mesoscale and Nanoscale Physics · Physics 2020-09-16 A. I. Nikitchenko , N. A. Pertsev

We measure the transport properties of two-dimensional ultracold Fermi gases during transverse demagnetization in a magnetic field gradient. Using a phase-coherent spin-echo sequence, we are able to distinguish bare spin diffusion from the…

Quantum Gases · Physics 2017-04-05 C. Luciuk , S. Smale , F. Böttcher , H. Sharum , B. A. Olsen , S. Trotzky , T. Enss , J. H. Thywissen

Results are reported from the HERMES experiment at HERA on a measurement of the neutron spin structure function $g_1^n(x,Q^2)$ in deep inelastic scattering using 27.5 GeV longitudinally polarized positrons incident on a polarized $^3$He…

High Energy Physics - Experiment · Physics 2008-11-26 The HERMES Collaboration , K. Ackerstaff

A systematic investigation of spin transport properties in silicon at 8 K by using a non-local geometry is presented. The spin injection signal in the non-local scheme is found to increase in proportion to the evolution of bias electric…

We have investigated charge and spin transport in n-type metallic GaAs nanowires (~ 10^17 cm^-3 doping level), grown by hydride vapor phase epitaxy (HVPE) on Si substrates. This was done by exciting the nanowire by tightly-focussed…

We study the effect of a magnetic insulator (Yttrium Iron Garnet - YIG) substrate on the spin transport properties of Ni$_{80}$Fe$_{20}$/Al nonlocal spin valve (NLSV) devices. The NLSV signal on the YIG substrate is about 2 to 3 times lower…

Mesoscale and Nanoscale Physics · Physics 2015-03-30 F. K. Dejene , N. Vlietstra , D. Luc , X. Waintal , J. Ben Youssef , B. J. van Wees

Graphitic nanostructures, e.g. carbon nanotubes (CNT) and graphene, have been proposed as ideal materials for spin conduction[1-7]; they have long electronic mean free paths[8] and small spin-orbit coupling[9], hence are expected to have…

Mesoscale and Nanoscale Physics · Physics 2007-12-05 Sungjae Cho , Yung-Fu Chen , Michael S. Fuhrer

Antiferromagnetic insulators (AFIs) are of significant interest due to their potential to develop next-generation spintronic devices. One major effort in this emerging field is to harness AFIs for long-range spin information communication…

The concept of anisotropy of spin relaxation in non-magnetic metals with respect to the spin direction of the injected electrons relative to the crystal orientation is introduced. The effect is related to an anisotropy of the Elliott-Yafet…

The temperature dependence of the spin relaxation time in multilayer graphene (MLG) spin valve devices was measured using a non-local magnetoresistance (NLMR) measurement. A weak localization (WL) was observed from magnetoresistance (MR)…

Mesoscale and Nanoscale Physics · Physics 2013-04-01 Takehiro Yamaguchi , Rai Moriya , Satoru Masubuchi , Kazuyuki Iguchi , Tomoki Machida

The magnetotransport in a set of identical parallel AlGaN/GaN quantum wire structures was investigated. The width of the wires was ranging between 1110 nm and 340 nm. For all sets of wires clear Shubnikov--de Haas oscillations are observed.…

Mesoscale and Nanoscale Physics · Physics 2009-11-13 P. Lehnen , Th. Schapers , N. Kaluza , N. Thillosen , H. Hardtdegen

The first direct evidence of an induced spin moment in Gd(62.4)Y(37.6) is presented. This additional moment, of 0.16 +/- 0.03 Bohr magnetons, arises from polarisation of Y electrons in the alloy. The moment was detected in a Compton…

Condensed Matter · Physics 2007-05-23 J. A. Duffy , S. B. Dugdale , J. E. McCarthy , M. A. Alam , M. J. Cooper , S. B. Palmer , T. Jarlborg

Spin orientation of photoexcited carriers and their energy relaxation is investigated in bulk Ge by studying spin-polarized recombination across the direct band gap. The control over parameters such as doping and lattice temperature is…

Materials Science · Physics 2013-07-24 F. Pezzoli , L. Qing , A. Giorgioni , G. Isella , E. Grilli , M. Guzzi , H. Dery

Time resolved measurements of magnetization in n-GaAs have revealed a rich array of spin decoherence processes, and have shown that fairly long lifetimes (\sim 100 ns) can be achieved under certain circumstances. In time-resolved Faraday…

Materials Science · Physics 2009-11-10 W. O. Putikka , R. Joynt

We report here an experimental and theoretical study on the magnetoresistance properties of heavily phosphorous doped germanium on the metallic side of the metal-nonmetal transition. An anomalous regime, formed by negative values of the…

We studied electrical transport in magnetic semiconductors, which is determined by scattering of free carriers off localized magnetic moments. We calculated the scattering time and the mobility of the majority and minority-spin carriers…

Materials Science · Physics 2007-05-23 M. Foygel A. G. Petukhov

We identify and investigate thermal spin transport phenomena in sputter-deposited Pt/NiFe$_2$O$_{\textrm{4-x}}$ ($4\geq x \geq 0$) bilayers. We separate the voltage generated by the spin Seebeck effect from the anomalous Nernst effect…