Collaborative Research: Spin Transport in Nonrelatisvistically Spin-split Antiferromagnets

University Of Nebraska-Lincoln, Lincoln NE

Investigators

Abstract

NON-TECHNICAL SUMMARY In his 1970 Nobel Prize Lecture, Louis Néel famously described antiferromagnets – materials with nearby magnetic moments of atoms being oriented in opposite directions, as interesting but useless. This is due to their vanishing net magnetic moment which makes difficult to control properties of antiferromagnets by an applied magnetic field. Jump forward 50 years, antiferromagnets have emerged as potential replacements for ferromagnets – materials with magnetic moments of atoms being oriented in the same direction, in commercial memory applications. Unlike ferromagnets, antiferromagnets can improve speed and storage density by orders of magnitude. However, harnessing this potential requires the development of efficient information write and read-out protocols for antiferromagnets, which is much more challenging than those used for ferromagnets. This project addresses this challenge by exploiting unique properties of a newly discovered class of antiferromagnets that exhibit an uncompensated magnetic moment along certain crystal directions. While the net magnetic moment of these antiferromagnets remains vanishing, this property allows similar information write and read-out protocols as those used for ferromagnets, provided that the methods to grow single-crystal films of these antiferromagnets have been successfully developed. This collaborative project brings together the experimental and theoretical expertise of the University of Delaware and University of Nebraska-Lincoln with the ultimate goal of developing a memory cell based on this new class of antiferromagnets. The collaborative research will elucidate the unique properties of this new class of antiferromagnets and holds potential to revolutionize information processing and storage. The project will provide valuable training in modern experimental and theoretical methods for early career team members, preparing them for cutting-edge research in materials science. The project emphasizes the inclusion of students from underrepresented minority groups, providing them with exposure to advanced interdisciplinary studies and enriching their professional preparation. The research team will collaborate with industrial researchers offering intellectual stimulus and an important educational component regarding career opportunities in industry. Leveraging the existing program at University of Delaware, the team will outreach to high schools, engaging minority high-school students and inspiring their interest in science and engineering. Additionally, team members will actively participate in the NSF-funded Partnerships for Research and Education in Materials (PREM) program between the University of Nebraska-Lincoln and Tuskegee University. Results of the proposed research will be disseminated to a broader audience via modern multimedia channels including an NSF-supported online resource Funsize Physics. TECHNICAL SUMMARY Antiferromagnets hold great potential for replacing ferromagnets in spintronic device applications due to their orders of magnitude enhanced switching speed and storage density. Realizing this potential requires the development of efficient electric control and detection of the antiferromagnets order parameter, known as the Néel vector, which is much more challenging than the control and detection of the magnetization in ferromagnets. This proposal addresses this challenge by exploiting unique properties of the antiferromagnetic materials that belong to a space group supporting momentum-dependent spin splitting. Among them is RuO2 – the roomtemperature antiferromagnetic metal, exhibiting spin splitting of its electronic bands along certain crystallographic directions. The proposal entails a collaborative effort involving experimental and theoretical research, with the goal of harnessing the advantages offered by these nonrelativistically spin-split antiferromagnets. The ultimate goal is to demonstrate the electrical control and detection of the Néel vector, culminating in the realization of a fully functional antiferromagnetic tunnel junction with a large tunneling magnetoresistance at room temperature. By fundamentally advancing our understanding of the physics and materials science underlying these phenomena, the proposed research will contribute to the technological development of spintronic devices with superior performance. The research team will collaborate with industrial researchers providing intellectual stimulus and valuable insights into potential career opportunities in industry. Additionally, the project will equip early career team members with necessary skills in modern experimental and theoretical methods, essential for conducting research at the frontiers of materials science. The project emphasizes the inclusion of students from underrepresented minority groups, providing them with exposure to advanced interdisciplinary studies and enriching their professional preparation. Leveraging the existing program at University of Delaware, the team will reach out to high schools, engaging minority high-school students and inspiring their interest in science and engineering. Furthermore, team members will actively participate in the NSF-funded Partnerships for Research and Education in Materials (PREM) program between University of Nebraska-Lincoln and Tuskegee University. Results of the proposed research will be disseminated to a broader audience via modern multimedia channels including an NSF-supported online resource Funsize Physics. 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.