Spin precession and inverted Hanle effect in a semiconductor near a finite-roughness ferromagnetic interface

Dash, Saroj P.; Sharma, Sandeep; Breton, J. C. Le; Peiro, Julian; Jaffrès, Henri; George, Jean-Marie; Lemaı̂tre, A.; Jansen, R.

doi:10.1103/physrevb.84.054410

Cited by 185 publications

(257 citation statements)

References 46 publications

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“…3 This explains the large amount of work on spintronics with hybrid metal/semiconductor heterostructures for the past ten years, once it was proposed to solve the problem of impedance mismatch 4 by the use of an interface resistance, typically a tunneling barrier. [5][6][7] Various experiments have been performed to detect by electrical (e.g., the electrical Hanle effect) or by optical means a spin-polarized current injected from a ferromagnetic reservoir into a III-V semiconductor through an Al 2 O 3 barrier, [8][9][10][11][12] through MgO, [12][13][14][15][16] and through GaO, 17 or into Si through Al 2 O 3 (Refs. [18][19][20][21][22] and SiO 2 (Refs.…”

Section: Introductionmentioning

confidence: 99%

Spin injection at remanence into III-V spin light-emitting diodes using (Co/Pt) ferromagnetic injectors

et al. 2012

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We have studied the perpendicular magnetic anisotropy of Co/Pt multilayers and the electron spin injection efficiency by optical spectroscopy from a [Co(0.6 nm)/Pt(1 nm)] 4 /Fe(0.3 nm)/MgO perpendicular tunnel spin injector grown on AlGaAs/GaAs semiconductor light-emitting diodes. We observe a 2.5% circular polarization at low temperature close to the magnetic remanence when the 0.3 nm Fe film of the ferromagnetic injector is sufficiently thin to maintain the magnetization out of plane. The acquired squared magnetization cycle is explained by the remaining interlayer exchange coupling existing between Fe and the (Co/Pt) multilayer through Pt or possible perpendicular magnetic anisotropy at the MgO/Fe interface. The corresponding spin polarization of the current is then estimated as 7%, measured by photoluminescence techniques, after the necessary uprenormalization, taking into account the electron spin-flip rate in the quantum well. In contrast, no circular polarization is observed when the thin Fe layer is removed and despite the rather high magnetic polarizability of the 5d 9 electronic open shell of Pt at the interface with MgO. This emphasizes the reduced size of tunneling branching of wave functions at the interface, of the order of the atomic plane unit.

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Section: Introductionmentioning

confidence: 99%

Spin injection at remanence into III-V spin light-emitting diodes using (Co/Pt) ferromagnetic injectors

et al. 2012

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“…19 Another possibility is that the spin lifetime is limited by contact effects such as inhomogeneous stray fields. 34 Due to its atomically thin nature, this could have a larger effect for graphene compared to semiconductor or metallic spin transport systems that are typically much thicker.…”

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Effect ofin situdeposition of Mg adatoms on spin relaxation in graphene

et al. 2013

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We have systematically introduced charged impurity scatterers in the form of Mg adsorbates to exfoliated single layer graphene and observe little variation of the spin relaxation times despite pronounced changes in the charge transport behavior. All measurements are performed on non-local graphene tunneling spin valves exposed in-situ to Mg adatoms, thus systematically introducing atomic-scale charged impurity scattering. While charge transport properties exhibit decreased mobility and decreased momentum scattering times, the observed spin lifetimes are not significantly affected indicating that charged impurity scattering is inconsequential in the present regime of spin relaxation times (∼1 ns).

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“…3a and 3b, significant normal Hanle signals (DV TH, normal ) with the Lorentzian line shape similar to that of DV EH (see Fig. 2a) were observed at 300 K. The inverted Hanle signals (DV TH, inverted ) 27,28 in B x (Figs. 3c and 3d), roughly half the magnitude of the DV TH, normal , were also clearly measured.…”

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confidence: 68%

“…Clear electrical Hanle signals (DV EH ) with a Lorentzian line shape are detected at RT. It should be noted that the full spin accumulation (Dm) consists of the inverted Hanle signal (DV EH, inverted ) in B x and the normal Hanle signal (DV EH, normal ) in B z 27,28 . As shown in Figs.…”

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Thermal Spin Injection and Accumulation in CoFe/MgO/n-type Ge Contacts

Jeon¹,

Min²,

Park³

et al. 2013

Extended Abstracts of the 2013 International Conference on Solid State Devices and Materials

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Understanding the interplay between spin and heat is a fundamental and intriguing subject. Here we report thermal spin injection and accumulation in CoFe/MgO/n-type Ge contacts with an asymmetry of tunnel spin polarization. Using local heating of electrodes by laser beam or electrical current, the thermally-induced spin accumulation is observed for both polarities of the temperature gradient across the tunnel contact. We observe that the magnitude of thermally injected spin signal scales linearly with the power of local heating of electrodes, and its sign is reversed as we invert the temperature gradient. A large Hanle magnetothermopower (HMTP) of about 7.0% and the Seebeck spin tunneling coefficient of larger than 0.74 meV K 21 are obtained at room temperature.T he tremendous power consumption and accompanying heat generation in current electronic devices requires alternative technologies to provide a solution for the energy issues and to realize the energy efficient electronics. Spintronics is a viable route for it, using the spin degree of freedom in addition to the conventional charge transport 1 . Recently another important ingredient, namely heat, appears on the stage. It has been reported that the temperature gradient and heat flow in ferromagnetic structures gives rise to a variety of spin related phenomena 2 . Understanding the interplay between heat and spin transport is a fundamental and intriguing subject but also offers unique possibilities for emerging electronics based on the combination of thermoelectrics and spintronics.Especially in SC-based spintronics, the functional use of heat provides a new route to inject and control of spin in semiconductors (SCs) 3 . The generation of non-equilibrium spin populations (i.e. spin accumulation) in nonmagnetic SC is a central issue of SC-based spintronics 1,3-5 . Significant progress has been made on the spin accumulation in various SC systems by means of circularly polarized light 4,6 , spin-polarized tunneling 7-13 , hotelectron spin filtering 14,15 , spin-orbit interaction 16,17 , or magnetization dynamics 18,19 .Intriguingly, Le Breton et al. 20 have reported a rather different mechanism for the spin accumulation, in which temperature difference across a ferromagnet (FM)/oxide/SC tunnel contact can induce the spin accumulation (Dm) in SC via Seebeck spin tunneling (SST). It was found that the SST effect, involving thermal transfer of spin angular momentum from FM to SC without a tunneling charge current, is a purely interface-related phenomenon of the tunnel contact and governed by the energy dependence of its tunnel spin polarization (TSP) 20 . This provides a conceptually new mechanism for the generation of Dm in SC as well as for the functional use of heat in spintronic devices 20 . The SST and thermal spin accumulation (Dm th ) in p-type SC (e.g., p-type Si) have been intensely studied, using a Ni 80 Fe 20 /Al 2 O 3 /SiO 2 /p-SC contact with the asymmetry in TSP of tunneling holes 20 . However, the counterpart of n-type SC still needs to be explored...

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Spin precession and inverted Hanle effect in a semiconductor near a finite-roughness ferromagnetic interface

Cited by 185 publications

References 46 publications

Spin injection at remanence into III-V spin light-emitting diodes using (Co/Pt) ferromagnetic injectors

Spin injection at remanence into III-V spin light-emitting diodes using (Co/Pt) ferromagnetic injectors

Effect ofin situdeposition of Mg adatoms on spin relaxation in graphene

Thermal Spin Injection and Accumulation in CoFe/MgO/n-type Ge Contacts

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