T. Trypiniotis

Electrically tunable spin injector free from the impedance mismatch problem

Injection of spin currents into solids is crucial for exploring spin physics and spintronics. There has been significant progress in recent years in spin injection into high-resistivity materials, for example, semiconductors and organic materials, which uses tunnel barriers to circumvent the impedance mismatch problem; the impedance mismatch between ferromagnetic metals and high-resistivity materials drastically limits the spin-injection efficiency. However, because of this problem, there is no route for spin injection into these materials through low-resistivity interfaces, that is, Ohmic contacts, even though this promises an 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 from Ni(81)Fe(19) through an Ohmic contact is demonstrated through dynamical spin exchange. Furthermore, we demonstrate that this exchange can be controlled electrically by applying a bias voltage across a Ni(81)Fe(19)/GaAs interface, enabling electric tuning of the spin-pumping efficiency.

Spin transport in germanium at room temperature

Spin-dependent transport is investigated in a Ni/Ge/AlGaAs junction with an electrodeposited Ni contact. Spin-polarised electrons are excited by optical spin orientation and are subsequently used to measure the spin dependent conductance at the Ni/Ge Schottky interface. We successfully demonstrate electron spin transport and electrical extraction from the Ge layer at room temperature.

Photoinduced inverse spin-Hall effect: Conversion of light-polarization information into electric voltage

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.

Static and dynamic magnetic properties of Ni80 Fe20 square antidot arrays

We have investigated both static and dynamic magnetic properties of square antidot arrays in a ferromagnetic thin-film structure of Au (2 nm)/

Electric control of the spin Hall effect by intervalley transitions

{\text{Ni}}_{80}{\text{Fe}}_{20}

Direct conversion of light-polarization information into electric voltage using photoinduced inverse spin-Hall effect in Pt/GaAs hybrid structure: Spin photodetector

(27.6 nm) on a

Localized Magnetic Fields in Arbitrary Directions Using Patterned Nanomagnets

{\text{SiO}}_{2}

High Throughput Biological Analysis Using Multi‐bit Magnetic Digital Planar Tags

500 nm/Si substrate using magneto-optic Kerr effect magnetometry, Brillouin light scattering (BLS), and micromagnetic simulations. The antidot patterns were

Efficient Spin Detection Across the Hybrid Co/GaAs Schottky Interface

1\text{ }\ensuremath{\mu}\text{m}

Spin current depolarization under high electric fields in undoped InGaAs

square holes arranged in two separate square lattices of dot separations