Speaker: Mehmet Cengiz Onbaşlı
Title: Controlling magnetism using epitaxial strain, laser or magnetic field pulses
Date/Time: 11 November 2020/ 13:40 - 14:30
Zoom: Meeting ID: 954 7996 2594
Abstract: Thin film insulating magnetic iron garnets enable new fundamental physics for efficient control of magnetism in previously unexplored frequencies and low energies. These materials also allow for cutting-edge applications for ultralow-power spin-based signal processing due to their ultralow damping and exchange coefficients, low Joule heating, and magnetotransport properties with broken time-inversion symmetry. Here, I overview our three recent studies on control of magnetism using epitaxial strain, femtosecond laser and magnetic field pulses. First, we demonstrate that our palette of available thin film magnetic iron garnets is much broader than previously known by systematically investigating the garnet substrate and film pairs and calculating their anisotropies. Thus, one can benefit from a much broader range of perpendicular magnetic anisotropies and saturation fields in magnetic insulators. Second, we show that femtosecond laser pulses could be used to efficiently control the remanent states of magnetic garnets or metallic nanowires. Thus, one may optically write analog magnetoresistance and electrically read for power-efficient neurosynaptic functionalities. Third, I present a magnetic field pulse-assisted method for sub-coercivity writing of magnetic iron garnet nanowires without thermal assistance. A nanomagnetic trilemma emerges among switching rate, energy and the external field required.
Bio:M. C. Onbaşlı got his B.S. and Ph.D. degrees from Bilkent University Dept. of Electrical & Electronics Engineering and Massachusetts Institute Technology Dept. Materials Science & Eng. in 2010 and 2015, respectively. Currently, he is an assistant professor of electrical and electronics engineering at Koç University. His research interests include engineering magnetic insulator iron garnet, nanometal, 2D transition metal dichalcogenide and topological insulator material properties to achieve ultralow power and efficient control of magnetism for advanced data storage, efficient artificial intelligence hardware and sensor chip applications. His research at Koç University Translational Medicine Research (KUTTAM) includes using advanced materials characterization capabilities such as Raman and other optical spectroscopies to assist neurosurgeons and pathologists in identifying and diagnosing tissue sections. He published nearly 100 peer-reviewed high-impact journal or conference papers and received awards including BAGEP, TUBA-GEBİP and European Research Council Starting Grant.