Spinorbitronics and spin-Hall effects in metallic multilayers for thz Emission & thz Applications

Spinorbitronics and spin-Hall effects in metallic multilayers for THz Emission & THz Applications

Henri JAFFRES

Unite Mixte de Physique CNRS / Thales

Campus de Polytechnique, 1,Avenue Augustin Fresnel, 91767 Palaiseau Cedex

Spin-orbit interactions in bulk heavy metals, or at Rashba interfaces (or Topological Insulators interfaces) are at the origin of intriguing physical phenomena like spin Hall effects (SHE) and Inverse Spin-Hall effects [1] as well as Inverse Edelstein Effects (IEE) [2] leading to spin-to-charge conversion near interfaces of and interface states. These novel spinorbitronics effects, investigated here, are presently of a large interest in order to develop THz emitter devices like recently demonstrated in international spintronics laboratories worldwide [3-5]. On the ground of a very recent literature, I will first present our main latest experimental investigations, refined analyses and models related to the SHE occurring in 3d transition ferromagnets/Pt heavy metals [6] and 3d/Au:W bilayers combining spin-pumping spin-current injection and IEE [7]. In a second part, I will discuss the spin-to-charge conversion at the interface of LaAlO₃/SrTiO₃ Oxide Rashba electron gas [8] and Fe/Ge(111) Rashba systems [9] mediated by both the linear and cubic Rashba (111 direction) interactions and scaled by the IEE length. In these experiments, the spin-pumping mechanism in the ferromagnetic resonance regime (FMR) allows spin-current injection along the perpendicular direction whereas the necessary spin-orbit field allows its efficient conversion to a lateral charge current. We will discuss the different possible mechanism leading to such spin-to-charge conversion [10].

[1] J. Sinova et al., Rev. Mod. Phys. 87, 1213 (2015)

[2] JC Rojas-Sanchez et al., Nat. Comm., 2013, 4, 2944

[3]T. Seifert et al. Nat. Phot. 2016, 10, 483–488

[4] T. J. Huisman et al., Nat. Nano, 2016, 11, 455.

[5] http://www.fz-juelich.de/pgi/pgi-1/EN/Home/home_node.html

[6] JC Rojas-Sanchez et al., Phys. Rev. Lett. 112, 106602 (2014)

[7] P. Laczowski et al., Appl. Phys. Lett. 2014, 104, 14240.

[8] E. Lesne et al., “Highly efficient and tunable spin-to-charge conversion through Rashba coupling at oxide interfaces”, Nat. Mat. in press 08/2016.

[9] S. Oyarzun et al., submitted to Nat. Com. 08/2016

[10] H. Jaffrès et al. to be published.