Veranstaltungsdetails

11.11.2015, 17:00
Jungiusstr. 11, Hoersaal AP

SFB 668 - Kolloquium

Dr. C. O. Avci (ETH, Zuerich):

Spin-orbit torques and magnetoresistance in normal-metal/ferromagnet bilayers

Spin-orbit torques and magnetoresistance in normal -metal/ferromagnet bilayers (Can Onur Avci, Laboratory for Magnetism and Interfaces Physics Department of Materials, ETH Zuerich/Switzerland) Recent demonstrations of magnetization switching driven by current - induced spin-orbit torques (SOTs) have drawn considerable attention in the field of spintronics [1,2]. The SOTs arise in structures with inversion asymmetry and are associated with the spin Hall and interfacial effects [3]. They have been found to occur in a variety of normal -metal/ferromagnet (NM/FM) systems such as Pt/Co, Ta/CoFeB [1-3]. Another interesting subject concerning NM/FM systems, which enjoys a renewed interest, is the magnetoresistance. Our progressive understanding of spin-orbit coupling and the discovery of interface [4] and spin Hall driven [5] magnetoresistance effects have opened up new perspectives and revealed new physics in this old known phenomenon. My talk will focus on the above two active subjects of spintronics. In the first part of my discussion I will give a general introduction to spin-orbit torques and present our latest results on Pt and Ta-based layers, together with the all-electrical harmonic detection technique that we have developed in our lab. In the second part, I will discuss the magnetoresistance results obtained in similar systems where I will show that different manifestations of spin-orbit coupling give rise to linear and nonlinear magnetoresistance effects, such as our latest discovery: unidirectional spin Hall magnetoresistance [6,7]. [1] Miron et al., Nature 476, 189 (2011). [2] Liu et al., Science 336, 555 (2012). [3] Garello et al., Nature nanotech. 8, 587?593 (2013). [4] Kobs et al., Phys. Rev. Lett. 106, 217207 (2011). [5] Nakayama et al., Phys. Rev. Lett. 110, 206601 (2013). [6] Avci et al., Nature Phys. 11, 570-575(2015). [7] Avci et al. to appear in Appl. Phys. Lett.(arXiv:1510.06285).