DMREF: GOALI: Designing Materials for Next-generation Spintronic Devices

Non-technical Description: Feynman's visionary keynote speech emphasized the need for probabilistic computers to simulate complex, inherently probabilistic problems. This project addresses the challenge of developing hardware capable of accelerating probabilistic algorithms. By designing probabilistic bits (p-bits) based on stochastic low barrier magnets in magnetic tunnel junctions (MTJs), the research aims to realize a breakthrough in probabilistic computing. The proposed materials foundation focuses on identifying novel soft magnetic Heusler alloys with ultra-low energy barriers that can be controlled using energy-efficient spin-orbit torque (SOT) materials. This interdisciplinary endeavor integrates theoretical modeling, high-throughput materials screening, computational simulations, experimental synthesis and characterization, and modular simulations to accelerate materials discovery and device design for p-bit implementation. The transformative potential of this research lies in enabling compact and energy-efficient hardware for probabilistic computing, with implications for the semiconductor industry and expanding the material base for industry-relevant spintronic memory technologies. Research results produced by this work will be available to the wider community through the nanoHUB spintronics portal and gained knowledge will be disseminated through its educational platform that has offered courses to thousands of students and engineers. Moreover, student training and workforce development will be enhanced through a planned summer school. Technical Description: The objective of this research is to target technologically relevant high-performance p-bits by designing key material components. Heusler alloys are a remarkable class of more than 1500 intermetallic compounds whose magnetic properties can be readily tuned via both alloy composition and band structure engineering. In particular, Heusler properties are desirable for achieving high frequency fluctuations, because low magnetization, half-metallicity, nearly zero magneto-crystalline anisotropy, and exchange field-enhanced spin dynamics can all be realized in these materials. In addition, a number of Heusler materials exhibit excellent lattice matching to MgO used as a tunnel barrier in MTJs with high tunneling magneto resistance, as well as to highly efficient SOT materials. As an outcome of the proposed materials search and optimization, we expect to demonstrate p-bits with characteristic fluctuation frequencies up to tens of GHz controlled by SOT materials with improved efficiencies. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.