Energy-efficient switching of magnetization is a central problem in nonvolatile magnetic storage and magnetic neuromorphic computing. In the past two decades, several efficient methods of magnetic switching were demonstrated including spin torque, magneto-electric, and microwave-assisted switching mechanisms. Here we experimentally show that low-dimensional magnetic chaos induced by alternating spin torque can strongly increase the rate of thermally-activated magnetic switching in a nanoscale ferromagnet. This mechanism exhibits a well-pronounced threshold character in spin torque amplitude and its efficiency increases with decreasing spin torque frequency. We present analytical and numerical calculations that quantitatively explain these experimental findings and reveal the key role played by low-dimensional magnetic chaos near saddle equilibria in enhancement of the switching rate. Our work unveils an important interplay between chaos and stochasticity in the energy assisted switching of magnetic nanosystems and paves the way towards improved energy efficiency of spin torque memory and logic.
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http://dx.doi.org/10.1038/s41467-019-08444-2 | DOI Listing |
Adv Mater
January 2025
Department of Materials Science and Engineering, University of Wisconsin-Madison, Madison, Wisconsin, 53706, USA.
Unconventional spin-orbit torques arising from electric-field-generated spin currents in anisotropic materials have promising potential for spintronic applications, including for perpendicular magnetic switching in high-density memory applications. Here, all the independent elements of the spin torque conductivity tensor allowed by bulk crystal symmetries for the tetragonal conductor IrO are determined via measurements of conventional (in-plane) anti-damping torques for IrO thin films in the high-symmetry (001) and (100) orientations. It is then tested whether rotational transformations of this same tensor can predict both the conventional and unconventional anti-damping torques for IrO thin films in the lower-symmetry (101), (110), and (111) orientations, finding good agreement.
View Article and Find Full Text PDFEur Phys J C Part Fields
January 2025
Department of Physics, University of Alberta, Edmonton, AB T6G 2E1 Canada.
We analyze the angular momentum balance for a particle undergoing Thomas precession. The relationships among relativistic torque, the center of mass, and the center of inertia for a spinning particle are clarified. We show that spin precession is accompanied by orbital angular momentum precession, and present examples of the resulting out-of-plane motion.
View Article and Find Full Text PDFNano Lett
January 2025
School of Microelectronics, University of Science and Technology of China, Hefei 230026, People's Republic of China.
Spin-orbit torque (SOT) is widely considered to be a fast and robust writing scheme for magnetic random-access memories (MRAMs). However, the requirements of field-free switching and high switching efficiency are often incompatible in SOT devices, placing a critical challenge on its improvement. Here we propose that by utilizing biaxial systems the dilemma between high-efficiency and external-field-free SOT switching can be solved intrinsically.
View Article and Find Full Text PDFAm J Sports Med
January 2025
Midwest Orthopaedics at Rush, Chicago, Illinois, USA.
Background: Elbow injuries are prevalent among professional baseball pitchers as nearly 25% undergo ulnar collateral ligament reconstruction. Pitch type, ball velocity, and spin rate have been previously hypothesized to influence elbow varus torque and subsequent risk of injury, but existing research is inconclusive.
Purpose: To examine elbow varus torque, cumulative torque, and loading rate within professional pitchers throwing fastball, curveball, change-up, and slider pitches, as well as to identify potential influences of ball spin on the elbow.
Mater Horiz
January 2025
School of Materials Science and Engineering, Key Laboratory of Advanced Materials and Devices for Post-Moore Chips, Ministry of Education, University of Science and Technology Beijing, Beijing 100083, China.
Realizing spin-orbit torque (SOT)-driven magnetization switching offers promising opportunities for the advancement of next-generation spintronics. However, the relatively low charge-spin conversion efficiency accompanied by an ultrahigh critical switching current density () remains a significant obstacle to the further development of SOT-based storage elements. Herein, spin absorption engineering at the ferromagnet/nonmagnet interface is firstly proposed to achieve high SOT efficiency in Pt/Co/Ir trilayers.
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