Electrical control of nontrivial textures in magnetic nanostructures

Emory University, Atlanta GA

Investigators

Abstract

Nontechnical description: The technological demand for smaller and faster devices capable of new functionalities drives the scientific exploration of the nontrivial states of matter that remain stable when scaled down to just a few nanometers. The Project studies the skyrmions - nontrivial nanoscale magnetic textures that cannot by annihilated by a continuous evolution of magnetization. Such textures can be as small as a few nanometers, making it difficult to study them by the conventional microscopy techniques, and consequently very little is known about their properties or how they can be used in nanodevices. The Project uses magnetoelectronic measurements in nanofabricated structures to access the relevant length sales, and investigate the possibility to use electrical current locally injected into ultrathin magnetic films to create, manipulate, and detect skyrmions. The research is integrated with the training for undergraduate and graduate students, and contributes to the burgeoning broader nanoscience research, education and outreach efforts in the Atlanta area. Technical description: The Project investigates magnetic skyrmions - topologically nontrivial states in magnetic materials, which cannot be obtained by a continuous transformation of "trivial" states, and thus exhibit higher stability, unusual dynamical characteristics and response to perturbations. The research utilizes nanofabricated magnetic nanostructures based on ultrathin magnetic films with perpendicular anisotropy, and magnetoelectronic techniques to generate, characterize, and manipulate both static and dynamical states of skyrmions by electrical current. Materials science and magnetic engineering are used to achieve a significant Dzyaloshinskii-Moriya interaction capable of stabilizing skyrmions in the absence of current. New measurement approaches, such as three-terminal Hall effect , are designed specifically to investigate phenomena on nanoscale not accessible with the established techniques. This research provides fundamental insight into the effects of topological textures on the material properties, and develops routes for their experimental exploration as well as possible applications in nanoscale magnetoelectronic (spintronic) devices. In addition to directly training two graduate students, the impact of the Project is significantly enhanced by its role in supporting the free shared condensed matter and nanoscience research facilities provided by the PI to researchers at Emory University and in the larger Atlanta area, research involvement of undergraduates and high school students, and contribution the large special events such as the Atlanta Science Festival and the Elementary School Science Day.