Search for: All records

Spin-torque ferromagnetic resonance (ST-FMR) has been widely used for measuring damping-like spin–orbit torques in magnetic bilayers. Typically, the ratio between the damping-like and field-like spin–orbit torques are extrapolated based on the ferromagnetic resonance line shapes. However, when the field-like spin–orbit torque is unknown, the line shape analysis may lead to errors in extrapolating the damping-like spin–orbit torque. Here, we propose a modified version of the ST-FMR that allows extrapolation of both damping-like and field-like torques independently. By introducing an alternating current to the sample, the RF impedance is modulated, allowing detection via the reflected microwave. We show that the extrapolated field-like and damping-like torques in Py/Pt samples are consistent with the technique measuring current-induced linewidth and resonance field change but have much better signal-to-noise ratio. Our proposed method paves a way for more accurate measurement of spin–orbit torques. 

Abstract Magnonicsis a research field that has gained an increasing interest in both the fundamental and applied sciences in recent years. This field aims to explore and functionalize collective spin excitations in magnetically ordered materials for modern information technologies, sensing applications and advanced computational schemes. Spin waves, also known as magnons, carry spin angular momenta that allow for the transmission, storage and processing of information without moving charges. In integrated circuits, magnons enable on-chip data processing at ultrahigh frequencies without the Joule heating, which currently limits clock frequencies in conventional data processors to a few GHz. Recent developments in the field indicate that functional magnonic building blocks for in-memory computation, neural networks and Ising machines are within reach. At the same time, the miniaturization of magnonic circuits advances continuously as the synergy of materials science, electrical engineering and nanotechnology allows for novel on-chip excitation and detection schemes. Such circuits can already enable magnon wavelengths of 50 nm at microwave frequencies in a 5G frequency band. Research into non-charge-based technologies is urgently needed in view of the rapid growth of machine learning and artificial intelligence applications, which consume substantial energy when implemented on conventional data processing units. In its first part, the 2024 Magnonics Roadmap provides an update on the recent developments and achievements in the field of nano-magnonics while defining its future avenues and challenges. In its second part, the Roadmap addresses the rapidly growing research endeavors on hybrid structures and magnonics-enabled quantum engineering. We anticipate that these directions will continue to attract researchers to the field and, in addition to showcasing intriguing science, will enable unprecedented functionalities that enhance the efficiency of alternative information technologies and computational schemes.