Spin-orbit Torques Using Two-Dimensional Materials

Abstract

The manipulation of magnetization using electric currents is very promising for applications in magnetic memory devices. In these devices, consisting of a material with high spin-orbit coupling and a ferromagnet, a charge current is capable of efficiently controlling the magnetization direction via spin-orbit torques. In addition to applications, the study of spin-orbit torques can be used to discover new spintronic properties of materials, such as new mechanisms for charge-to-spin conversion.

The large family of layered two-dimensional materials has shown to contain excellent candidates for the generation of spin-orbit torques. They provide atomically-flat single crystals with various properties and pristine interfaces, leading to efficient magnetization manipulation of an adjacent ferromagnet.

In this talk I will show how the crystal structure, and electronic and magnetic properties of two-dimensional materials can be used to control the magnitude, direction, and symmetries of spin-orbit torques. I will discuss results for devices using low-symmetry transition metal dichalcogenides (WTe2 or NbSe2) where the spin-orbit torques are dictated by the crystal symmetry. Moreover, I will also present recent results showing a strong interaction between a 3D ferromagnet (NiFe) and a 2D semiconductor (WSe2), which results in interfacial spin-orbit torques and a strong magnetic anisotropy.

Marcos H. D. Guimarães is an Assistant Professor at the Zernike Institute for Advanced Materials of the University of Groningen. He is the principal investigator (PI) of the research group Opto-Spintronics of Nanostructures, studying the interplay between light, electron charge and spin, in nanostructures and devices.

Marcos Guimarães studied at the Federal University of Minas Gerais in Brazil, where he obtained a Bachelor and Master degrees in Physics. He received his PhD degree in 2015 from the University of Groningen, The Netherlands, working on “Spin and Charge Transport in Graphene Devices”. After being awarded two personal research grants, the Dutch NWO Rubicon, and a Kavli Institute Fellowship from the USA, he moved to Cornell University, USA, where he expanded his research focus to other two-dimensional materials and studied them using a variety of optical and electrical techniques. In 2017 Marcos received a NWO VENI grant and returned to the Netherlands where he further extended his experimental background studying ultrafast optics in two-dimensional materials at the Eindhoven University of Technology. In February 2019 he joined the Zernike Institute for Advanced Materials as an Assistant Professor in the group of Physics of Nanodevices. His research focuses on the magnetic and spintronic properties of two-dimensional materials and metallic thin films studied by magneto-optical and electrical means.

Zoom access (please access meeting 5 minutes prior to the start) | Meeting ID: 970 4329 5576 | Passcode: 289739