New Physics in Artificial Spin Ice via Materials Innovation

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Non-Technical AbstractMagnetic materials are extremely important technologically, and magnets that have size scale in the range of nanometers are especially important in a range of applications, such as hard disk drives. The fundamental physics of such tiny “nanomagnets” is also exciting, because collections of them show behavior that cannot be observed in any other physical system and can be controlled very precisely. Collections of these nanomagnets in certain carefully designed arrays are called “artificial spin ice” because they share some underlying physics with water molecules in ice. This research program studies such artificial spin ice composed of carefully chosen materials that result in a wide range of unusual behavior that would otherwise be inaccessible and could have significant technological implications once explored and understood. While the vast majority of prior research in this area uses only simple magnetic materials, this work will introduce more exotic materials to access specific, unusual, and potentially useful physics. Aside from connections to possible technologies, the research will also contribute substantially to the education of both undergraduate and graduate students, and the research efforts will inform the investigators’ work on behalf of the larger research ecosystem in the nation.Technical Abstract The research program will significantly expand the physics that can be probed in artificial spin ice by fabricating arrays from strategically chosen, innovative ferromagnetic materials through a collaboration between two investigators with highly complementary expertise, in materials fabrication and characterization, and magnetic measurements. The research will focus on three thrusts: 1. New artificial spin ice physics enabled by magnetic moments that point out of the plane of the structures, exploring cooperative phenomena that are inaccessible with in-plane moments. 2. Artificial spin ice behavior and superparamagnetism in the regime of strongly-temperature-dependent magnetization. 3. Emergent materials-induced electronic transport phenomena through networks of connected artificial spin ice. The research findings may have technological relevance in new computing paradigms and in magnonics. Undergraduate and graduate student researchers will be deeply involved in the research efforts and will gain a range of skills to advance their professional development. Both investigators will also leverage their involvement in various activities to further support the national research community.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.