Jean-Philippe Attané

Spin Pumping and Inverse Spin Hall Effect in Platinum: The Essential Role of Spin-Memory Loss at Metallic Interfaces

Through combined ferromagnetic resonance, spin pumping, and inverse spin Hall effect experiments in Co|Pt bilayers and Co|Cu|Pt trilayers, we demonstrate consistent values of ℓsfPt=3.4±0.4  nm and θSHEPt=0.056±0.010 for the respective spin diffusion length and spin Hall angle for Pt. Our data and model emphasize the partial depolarization of the spin current at each interface due to spin-memory loss. Our model reconciles the previously published spin Hall angle values and explains the different scaling lengths for the ferromagnetic damping and the spin Hall effect induced voltage.

Electrical and thermal spin accumulation in germanium

In this letter, we first show electrical spin injection in the germanium conduction band at room temperature and modulate the spin signal by applying a gate voltage to the channel. The corresponding signal modulation agrees well with the predictions of spin diffusion models. Then, by setting a temperature gradient between germanium and the ferromagnet, we create a thermal spin accumulation in germanium without any charge current. We show that temperature gradients yield larger spin accumulations than electrical spin injection but, due to competing microscopic effects, the thermal spin accumulation remains surprisingly unchanged under the application of a gate voltage.

Spin Signal in Metallic Lateral Spin Valves Made by a Multiple Angle Evaporation Technique

We report on the fabrication of metallic lateral spin valves using different evaporation directions for respective ferromagnetic and nonmagnetic materials. In this way, we can fabricate and connect different nanowires through the same resist mask in a single evaporation sequence, avoiding interface contamination. With this technique and by reducing the wire widths down to 50 nm, we obtained spin signals as large as 24 mΩ at 77 K in devices with transparent interfaces. We studied the influence of the nonmagnetic metal. Spin signals are found to be much larger for Al and Cu than for Au-based devices.

Spin conductance of YIG thin films driven from thermal to subthermal magnons regime by large spin-orbit torque

N. Thiery, A. Draveny, V. V. Naletov, 2 L. Vila, J.P. Attané, C. Beigné, G. de Loubens, M. Viret, N. Beaulieu, 4 J. Ben Youssef, V. E. Demidov, S. O. Demokritov, 6 A. N. Slavin, V. S. Tiberkevich, A. Anane, P. Bortolotti, V. Cros, and O. Klein ∗ SPINTEC, CEA-Grenoble, CNRS and Université Grenoble Alpes, 38054 Grenoble, France Institute of Physics, Kazan Federal University, Kazan 420008, Russian Federation SPEC, CEA-Saclay, CNRS, Université Paris-Saclay, 91191 Gif-sur-Yvette, France LabSTICC, CNRS, Université de Bretagne Occidentale, 29238 Brest, France Department of Physics, University of Muenster, 48149 Muenster, Germany Institute of Metal Physics, Ural Division of RAS, Yekaterinburg 620041, Russian Federation Department of Physics, Oakland University, Michigan 48309, USA Unité Mixte de Physique CNRS, Thales, Université Paris-Saclay, 91767 Palaiseau, France (Dated: September 19, 2017)

Geometrical control of pure spin current induced domain wall depinning

We investigate the pure spin-current assisted depinning of magnetic domain walls in half ring based Py/Al lateral spin valve structures. Our optimized geometry incorporating a patterned notch in the detector electrode, directly below the Al spin conduit, provides a tailored pinning potential for a transverse domain wall and allows for a precise control over the magnetization configuration and as a result the domain wall pinning. Due to the patterned notch, we are able to study the depinning field as a function of the applied external field for certain applied current densities and observe a clear asymmetry for the two opposite field directions. Micromagnetic simulations show that this can be explained by the asymmetry of the pinning potential. By direct comparison of the calculated efficiencies for different external field and spin current directions, we are able to disentangle the different contributions from the spin transfer torque, Joule heating and the Oersted field. The observed high efficiency of the pure spin current induced spin transfer torque allows for a complete depinning of the domain wall at zero external field for a charge current density of [Formula: see text] A m-2, which is attributed to the optimal control of the position of the domain wall.