Colloquium: Dr. Mehmet Cengiz Onbasli, Koc University

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.