Relativity road to future technology: how the spin Hall effect and spin-orbit torque are shaping new possibilities for information storage
Prof. Dr. Jairo Sinova (Institut für Physik, Universität Mainz)

Understanding the origin and properties of the different phases of materials and how to control them is at the heart of condensed matter physics. One of the grand challenges of the field is controlling spin-dependent properties without using magnetic fields. To do so, one can resort to the spin-orbit coupling (SOC), which is one of the few echoes of special relativity in condensed-matter physics that connects the spin and charge of the electron. We have learned how to exploit SOC to create new paradigms of spin control in complex materials and discover new unexpected links between seemingly disparate ideas as topology, materials science, ferromagnetism, thermoelectricity, and current-induced magnetization manipulation. I will broadly describe joint theoretical and experimental efforts on how we use SOC to generate and manipulate spin-currents that are now being used in devices relevant for future MRAM technology. I will also show in some detail how insights on the spin Hall effect1,2 have yielded novel ways to manipulate magnetization using the intrinsic spin-orbit torque,5 and how to extend these ideas to a new a phase of spintronics by exploiting anti-ferromagnetic materials in an active way, creating memory and computing devices that are insensitive to external magnetic fields.

References:

1. N. Nagaosa, Jairo Sinova, S. Onoda, A. H. MacDonald, and P. Ong, “Anomalous Hall Effect”, Rev. of Mod. Phys. 82, 1539 (2010).
2. J. Wunderlich, B. G. Park, A. C. Irvine, L. P. Zarbo, E. Rozkotova, P. Nemec, V. Novak, Jairo Sinova, T. Jungwirth, “Spin Hall effect transistor”, Science 330, 1801 (2010).
3. J. Wunderlich, A. C. Irvine, Jairo Sinova, B. G. Park, X. L. Xu, B. Kaestner, V. Novak, and T. Jungwirth, “Spin-injection Hall effect in a planar photovoltaic cell”, Nature Physics 5, 675 (2009).
4. H. Kurebayashi, Jairo Sinova, D. Fang, A. C. Irvine, J. Wunderlich, V. Novak, R. P. Campion, B. L. Gallagher, E. K. Vehstedt, L. P. Zarbo, K. Vyborny, A. J. Ferguson, T. Jungwirth, “Observation of a Berry phase anti-damping spin-orbit torque”, Nature Nanotechnology (2014).
5. J. Zelezny, H. Gao, K. Vyborny, J. Zemen, J. Masek, A. Manchon, J. Sinova, and T. Jungwirth, “Relativistic Neel-order fields induced by electrical current in antiferromagnets”, submitted for publication