1Injection of spin currents into solids is crucial for exploring spin physics and spintronics 1,2 . There has been significant progress in recent years in spin injection into high-resistivity materials, e.g., semiconductors and organic materials, which uses tunnel barriers to circumvent the impedance mismatch problem 3-14 ;the impedance mismatch between ferromagnetic metals and high-resistivity materials drastically limits the spin-injection efficiency 15 . However, because of this problem, there is no route for spin injection into these materials through low resistivity interfaces, i.e., ohmic contacts, even though it promises easy and versatile pathway for spin injection without the need for growing high-quality tunnel barriers. Here we show experimental evidence that spin pumping enables spin injection free from this condition; room-temperature spin injection into GaAs Electron transport across a ferromagnetic metal/nonmagnetic material gives rise to nonequilibrium spin currents in the nonmagnetic layer. However, the spin polarization of the current across the interface is strongly reduced especially when the electrical resistance of these two layers is considerably different, e.g., a ferromagnetic metal/semiconductor (FM/SC) contact. This is known as the impedance mismatch problem 3,15 .The above problem arises from the fact that spins are injected by carrier transport across a FM/SC interface (see Fig. 1a). It seems natural to consider that this problem disappears when spins are injected directly into the SC layer without using charge transport across the interface (see Fig. 1b); the driving force for the spin flow (not the charge carrier flow)is expected to offer a way for versatile spin injection free from the impedance mismatch problem. In this work, we experimentally demonstrate that the spin pumping, generation of pure spin currents from magnetization precession [16][17][18] , provides a powerful way for direct spin injection. The spin-angular momentum of the precessing magnetization in the FM layer is transferred to the carriers in the SC layer via dynamical exchange interaction at the FM/SC interface, inducing a pure spin voltage, the potential acting on spins not on carriers, in the SC layer. This enables spin injection into both p-and n-doped GaAs from We measured the ferromagnetic resonance (FMR) signal and the electric-potential difference V between the electrodes attached to the GaAs layer to detect spin injection; as shown in Fig. 2a, in the FMR condition, the dynamical exchange interaction drives the spin pumping, injecting pure spin currents into the GaAs layer through the ohmic and Schottky contacts. This spin current flows in the GaAs layer, giving rise to an electromotive force E ISHE in the GaAs layer via the ISHE. In the ISHE process, when the spin current carries the spin polarization σ along the spatial direction j s , E ISHE is given byHere, the dc component of σ is parallel to the magnetization-precession axis in the Ni 81 Fe 19 layer and j s is along the normal direction to the film...

The control of magnetic order in nanoscale devices underpins many proposals for integrating spintronics concepts into conventional electronics. A key challenge lies in finding an energy-efficient means of control, as power dissipation remains an important factor limiting future miniaturization of integrated circuits. One promising approach involves magnetoelectric coupling in magnetostrictive/piezoelectric systems, where induced strains can bear directly on the magnetic anisotropy. While such processes have been demonstrated in several multiferroic heterostructures, the incorporation of such complex materials into practical geometries has been lacking. Here we demonstrate the possibility of generating sizeable anisotropy changes, through induced strains driven by applied electric fields, in hybrid piezoelectric/spin-valve nanowires. By combining magneto-optical Kerr effect and magnetoresistance measurements, we show that domain wall propagation fields can be doubled under locally applied strains. These results highlight the prospect of constructing low-power domain wall gates for magnetic logic devices.

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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 the interface. This pure spin current is, by the inverse spin-Hall effect in the Pt layer, converted into electric voltage. By changing the direction and ellipticity of the circularly polarized light, the electromotive force varies systematically, consistent with the prediction of the photoinduced inverse spin-Hall effect. The observed phenomenon allows the direct conversion of circular-polarization information into electric voltage; this phenomenon can be used as a spin photodetector.

Reacting N-aryliminophosphoranes with 1-(het)aroyl-2-aryldiazenes in preheated diphenyl ether at ca. 150-250 °C for 5-25 min affords in most cases the 1,3-diaryl-1,4-dihydrobenzo[e][1,2,4]triazin-4-yls (aka Blatter radicals) in moderate to good yields. All new compounds are fully characterized, including EPR and CV studies for the radicals. Single-crystal X-ray structures of 1-benzoyl-2-(perfluorophenyl)diazene and 1-(perfluorophenyl)-3-phenyl-1,4-dihydrobenzo[e][1,2,4]triazinyl are also presented.