Generation, transport and manipulation of spin currents in metals

CFM Seminars

Speaker

Felix Casanova (Ikerbasque Research Professor, CIC nanoGune)

When

2014/11/26
13:00

Place

Auditorium of the Centro de Fisica de Materiales, Paseo Manuel de Lardizabal 5, Donostia-San Sebastián

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# Generation, transport and manipulation of spin currents in metals ** ** _F. Casanova_ 1,2 1 _Nanodevices Group,CIC nanoGUNE, 20018, San Sebastian, Basque Country (Spain)_ 2 _IKERBASQUE, Basque Foundation for Science, 48011, Bilbao, Basque Country (Spain)_ _f.casanova@nanogune.eu_ __ Spintronics is a rapidly growing research area that aims at using and manipulating the spin of the electron. There is special interest in the creation, transport and manipulation of pure spin currents as an alternative to conventional electronics. One of the most robust experimental approaches is by using lateral spin valves (LSV). LSVs allow injection of a charge current from a ferromagnetic (FM) injector into a non-magnetic (NM) channel and measure the spin accumulation as a voltage from a second FM electrode by using a non-local geometry. We have optimized a nanofabrication process that yields highly reproducible LSV devices, crucial for reliable studies [1-3]. These studies include: i) the spin injection efficiency of different FM metals [1]; ii) quantification of the contributions to the spin relaxation in the NM channel [2]; iii) measurement of the Hanle effect (spin precession with an external magnetic field). With LSV devices we have also recently proposed a novel manipulation of spin currents with a magnetic gate, based on the spin-mixing conductance concept [3]. Alternatively, another promising effect is being studied for the spin current generation and detection: the spin Hall effect (SHE). This is a spin-dependent phenomenon appearing in materials with strong spin-orbit coupling (SOC) in which a charge current flowing through a non-magnetic material creates a spin current in the transverse direction to the charge current [4]. Reciprocally, a spin current through a non-magnetic material creates a transverse charge current (inverse SHE). We have studied the SHE in materials such as Pt and Au, and analyzed the dominant scattering mechanisms behind the SHE in these metals [4]. Finally, we have also studied the SHE in Bi, a semimetal with more exotic properties. Our results evidence that the observed spin-to-charge current conversion arises from the inverse Rashba-Edelstein effect occurring at the Bi surface, rather than the inverse SHE occurring at the bulk of Bi [5]. [1] E. Villamor _et al._ , Phys. Rev. B **88** , 184411 (2013). [2] E. Villamor _et al._ , Phys. Rev. B **87** , 094417 (2013). [3] E. Villamor _et al._ , arXiv: 1404.2311 (2014). [4] M. Isasa _et al._ , arXiv: 1407.4770 (2014). [5] M. Isasa _et al._ , arXiv: 1409.8540 (2014).