We perform a quantitative, comparative study of the spin pumping, spin Seebeck and spin Hall magnetoresistance effects, all detected via the inverse spin Hall effect in a series of over 20 yttrium iron garnet/Pt samples. Our experimental results fully support present, exclusively spin currentbased, theoretical models using a single set of plausible parameters for spin mixing conductance, spin Hall angle and spin diffusion length. Our findings establish the purely spintronic nature of the aforementioned effects and provide a quantitative description in particular of the spin Seebeck effect.Pure spin currents present a new paradigm in spintronics [1, 2] and spin caloritronics [3]. In particular, spin currents are the origin of spin pumping [4,5], the spin Seebeck effect [6,7] and the spin Hall magnetoresistance (SMR) [8][9][10]. Taken alone, all these effects have been extensively studied, both experimentally [6-9, 11-13] and theoretically [4,[14][15][16][17][18]. From a theoretical point of view, all these effects are governed by the generation of a current of angular momentum via a non-equilibrium process. The flow of this spin current across a ferromagnet/normal metal interface can then be detected. The relevant interface property that determines the spin current transport thereby is the spin mixing conductance. Nevertheless, there has been an ongoing debate regarding the physical origin of the measurement data acquired in spin Seebeck and SMR experiments due to possible contamination with anomalous Nernst effect [19][20][21] or anisotropic magnetoresistance [22,23] caused by static proximity polarization of the normal metal [23]. To settle this issue, a rigorous check of the consistency of the spin-current based physical models across all three effects is needed. If possible contamination effects are absent, according to the spin mixing conductance concept [24], there should exist a generalized Ohm's law between the interfacial spin current and the energy associated with the corresponding non-equilibrium process. This relation should invariably hold for the spin pumping, spin Seebeck and spin Hall magnetoresistance effects, as they are all based on the generation and detection of interfacial, nonequilibrium spin currents. We here put forward heuristic arguments that are strongly supported by experimental evidence for a scaling law that links all aforementioned spin(calori)tronic effects on a fundamental level and allows to trace back their origin to pure spin currents. (c) The spin Hall magnetoresistance is due to the torque exerted on M by an appropriately polarized Js which yields a change in the reflected spin current J r s . The interconversion between Js (J r s ) and the charge currents Jc (J r c ) are due to the (inverse) spin Hall effect in the normal metal.[schematically depicted in Fig. 1(a)], we place YIG / Pt bilayers in a microwave cavity operated at ν = 9.85 GHz to resonantly excite magnetization dynamics. The emission of a spin current density J s across the bilayer interface into the Pt provides...

The spin current pumped by a precessing ferromagnet into an adjacent normal metal has a constant polarization component parallel to the precession axis and a rotating one normal to the magnetization. The former is now routinely detected as a dc voltage induced by the inverse spin Hall effect (ISHE). Here we compute ac ISHE voltages much larger than the dc signals for various material combinations and discuss optimal conditions to observe the effect. The backflow of spin is shown to be essential to distill parameters from measured ISHE voltages for both dc and ac configurations. DOI: 10.1103/PhysRevLett.110.217602 PACS numbers: 76.50.+g, 72.25.Mk, 73.40.Àc In magnetoelectronics the electronic spin degree of freedom creates new functionalities that lead to applications in information technologies such as sensors and memories [1]. Central to much excitement in this field is the spin Hall effect (SHE) [2][3][4][5], i.e., the spin current induced normal to an applied charge current in the presence of spin-orbit interaction, as discovered optically in semiconductors [6,7] and subsequently electrically in metals [8][9][10]. Recently magnetization reversal by the SHE induced spin transfer torque has been demonstrated [11,12]. The generation of a voltage by a spin current injected into a paramagnetic metal, the inverse spin Hall effect (ISHE), can be employed to detect the spin current due to spin pumping [13][14][15] by an adjacent ferromagnet under ferromagnetic resonance (FMR) conditions [8,16]. The ISHE has also been essential for the discovery of the spin Seebeck effect [17].In recent experiments, dc voltages induced by the ISHE have been measured in many material combinations, thereby giving access to crucial parameters such as the spin Hall angle [18][19][20] and the spin mixing conductance [21], the material parameter determining, e.g., the effectiveness of interface spin-transfer torques [14]. For example, the magnitude and sign of the spin Hall angle has been determined for Permalloy ðPyÞjN bilayers for different normal metals N [18,19]. An approximate scaling relation for the spin pumping by numerous ferromagnets (F) has been discovered by comparing different FjPt bilayers as a function of excitation power [21]. However, it is far from easy to derive quantitative information from ISHE experiments [22]. As reviewed by the Cornell Collaboration [23], several experimental pitfalls should be avoided. At FMR, the dc ISHE voltage is small, scaling quadratically with the cone angle of the precessing magnetization. An important correction is caused by the back diffusion (''backflow'') of injected spins to the interface, which effectively reduces the spin current injection [14] and generates voltages normal to the interface [24,25]. This backflow has often been neglected in interpreting spin-pumping experiments, assuming that Pt, the metal of choice, can be treated like a perfect spin sink.The spin current injected by FMR into a normal metal consists of a dc component along the z axis parallel to the effective fiel...

A mesoscopic Coulomb blockade system with two transport channels is studied in terms of full counting statistics. It is found that the shot noise and skewness are crucially affected by the quantum mechanical interference. In particular, the super-Poisson behavior can be induced as a consequence of constructive interference, and can be understood by the formation of effective fast-and-slow transport channels. Dephasing and finite temperature effects are carried out together with physical interpretations.

We examine the full counting statistics of electron transport through double quantum dots coupled in series, with particular attention being paid to the unique features originating from level renormalization. It is clearly illustrated that the energy renormalization gives rise to a dynamic charge blockade mechanism, which eventually results in super-Poissonian noise. Coupling of the double dots to an external heat bath leads to dephasing and relaxation mechanisms, which are demonstrated to suppress the noise in a unique way.