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In this work, a scanning inverse spin Hall effect measurement system based on a shorted coaxial resonator has been built, which provides a high throughput method to characterize spin transport properties. The system is capable of performing spin pumping measurements on patterned samples within an area of 100 × 100 mm2. Its capability was demonstrated with Py/Ta bilayer stripes deposited on the same substrate with different thicknesses of Ta. The results show that the spin diffusion length is about 4.2 nm with a conductivity of about 7.5 × 105 Ω−1 m−1, which leads to the conclusion that the intrinsic mechanism of spin relaxation of Ta is the Elliott–Yafet interactions. The spin Hall angle of Ta is estimated to be about −0.014 at room temperature. The setup developed in this work provides a convenient, efficient, and nondestructive way to obtain the spin and electron transportation characteristics of the spintronic materials, which will fertilize this community by developing new materials and figuring out their mechanism. [ABSTRACT FROM AUTHOR]

Microwave power harvesting is one of the promising ways to solve energy problems in the future. Improving the power harvesting ability is the central work in this area. The inverse spin Hall effect (ISHE) in ferromagnetic (FM) and nonmagnetic (NM) metallic bilayers can be utilized to convert microwave power to direct current, which may be one of the candidates of microwave power harvesting. In this work, a FM/NM microstrip array is proposed to enhance the ISHE signal, while the spin rectification effect signal in the FM layer is suppressed. This enhancement is equivalent to connecting the power sources in series, namely, the ISHE voltage is proportional to the number of the FM/NM microstrips. Our work fertilizes the spintronics and shows the possibility to use ISHE in microwave power transfer and harvesting. [ABSTRACT FROM AUTHOR]

Microwave spin pumping at ferromagnetic resonance from ferromagnetic films into nonmagnetic films is an efficient method to realize spin injection. The spin injection efficiency is proportional to the spin mixing conductance and can be detected by measuring voltages converted from spin current via the inverse spin Hall effect. In this work, we modified the properties of the ferromagnetic layer by thermal annealing. The results show that the crystal quality of the ferromagnetic films, as well as the magnetic properties has been greatly modified while the spin mixing conductance is insensitive to it. The work represent an incentive to work on engineering the spin Hall angle of the nonmagnetic layer to improve the spin Hall effect or the inverse spin Hall effect. [ABSTRACT FROM AUTHOR]

• Distribution of induced microwave current in Py film depends on its geometry. • SRE signal can be neglected at specific magnetic field angle and geometry for Py film. • Pure ISHE signal can be obtained directly in Py(20 nm)/Ta(10 nm) bilayer (40 μm × 8 mm). • Spin Hall angle value of Ta in Py/Ta bilayer is similar to that of some literatures. We present a method to directly obtain the pure inverse spin Hall effect (ISHE) signal without the spin rectification effect (SRE) signal in ferromagnetic metal(FM)/nonmagnetic metal(NM) bilayers. This method is based on a fact that the distribution of the induced microwave current is largely dependent on the geometries of the samples. The ISHE signal can be maximized through shaping the samples and tuning the magnetic field directions, while the SRE signal can be minimized below the detection limit. This provides also a fast and simplified method to measure the ISHE signal in a wide frequency range. The spin Hall angle of Ta in a Py/Ta bilayer is −0.027 ± 0.015 in a wide frequency range. [ABSTRACT FROM AUTHOR]

We measured the spin rectification effect and the inverse spin Hall effect in Nb-doped SrTiO 3 by pumping the spins from the ferromagnetic thin films into SrTiO 3. The spin injection is increased when the doping level is increased. However, the spin to charge conversion efficiency which is measured by the spin Hall angle decreases when Nb concentration is more than ∼ 0.02 wt%. We argued that it is because that the electrons contributed to the inverse spin Hall effect are from the d − orbitals of Nb instead of Ti beyond this concentration. Our work points to the importance of orbital occupations in the (inverse) spin Hall effect. We may explore controllable spin and charge interconversion in oxide spintronics. • The spin currents can be converted into the charge current in Nb doped SrTiO 3. • The conversion efficiency is a function of the doping levels • The underlying mechanism is the multiorbital nature of the d-electrons [ABSTRACT FROM AUTHOR]