MRI: Development of a Broadband 330 GHz Variable Temperature Magnetic Resonance Spectrometer System

Ohio State University, The, Columbus OH

Investigators

Abstract

This Major Research Instrumentation award funds the development of a broadband high frequency magnetic resonance system with frequencies up to 330 gigahertz (GHz) at temperatures between liquid helium and room temperature. Magnetic resonance is one of the most important phenomena in materials and medical research, which have led to a broad range of applications in wireless communication, radar, navigation, remote sensing, wireless power transmission, and imaging diagnostics. Ferromagnetic resonance (FMR) and electron paramagnetic resonance (EPR) have been major characterization techniques for understanding the magnetic excitations and spin dynamics in fundamentally important and technologically relevant materials. Probing and understanding magnetic resonance properties of new materials and heterostructures are essential for developing transformative technologies, such as next generation information technology, telecommunication, and data storage, which have dramatically affected our everyday life. Currently, the vast majority of the magnetic resonance spectrometers are limited to a frequency range of 1-40 GHz. The instrument to be developed will enable broadband, variable frequency magnetic resonance measurements up to 330 GHz, bridging the gap between traditionally important GHz applications, e.g. cell phones and radar, and the new frontier of terahertz (THz) technologies. This will be the first magnetic resonance spectrometer within this frequency range at a shared user facility in the Midwest region, and will significantly strengthen and expand the investigation of novel fundamental phenomena and the development of paradigm-changing technologies for researchers at The Ohio State University and from across the Midwest region. In addition, the development of this instrument will offer a rare opportunity to train a large number of postdoctoral researchers, graduate and undergraduate students to become experts in high frequency magnetic resonance technologies and microwave instrumentation, filling a vital national need. This instrument will play an important role in a number of outreach programs at Ohio State to attract and nurture women and underrepresented minority students in scientific research. Supported by this MRI award, a research team at The Ohio State University will develop a broadband, high sensitivity magnetic resonance spectrometer system which will provide an indispensable in-house tool for studying magnetic excitations, dynamic spin transport and microwave device applications. It will enable investigations of a wide array of novel materials and structures for a large number of research groups at The Ohio State University and other institutions in the region. The MRI team will design and build a series of magnetic resonance cavities with resonant frequencies between 10 and 320 GHz for operation in a cryogenic 14 tesla superconducting magnet, which offers access to a previously unexplored regime for revealing the underlying mechanisms responsible for the magnonic behavior and dynamically generated spin currents in heterostructures of ferromagnets, antiferromagnets, topological insulators, skyrmions, and nonmagnetic materials. This instrument will be located in the NanoSystems Laboratory (NSL), a well-run user facility at Ohio State that is open to all academic and industrial users. The instrument will enable transformative research in novel regimes of spintronics utilizing high speed, high efficiency, coherent spin transport and extraordinary dynamic spin manipulation in spin-textured materials such as topological insulators and skyrmions. These insights will provide the foundation for developing next generation spin-electronic devices