Synthesis of Metastable New Materials Without Critical Elements for Applications in Superconductivity and Magnetism

The synthesis of new compounds via stabilization of kinetic phases has potential for transformative impact across materials chemistry. For the purposes of this proposal, we will focus on two specific applications of novel metastable compounds: superconductivity and permanent magnets. Both superconductors and permanent magnets share a reliance on critical materials, specifically, rare-earth elements. The design of new superconductors and permanent magnets without rare-earth elements would create revolutionary materials for vital applications while reducing our reliance on geopolitically inaccessible elements. Within both categories, there are promising conceptual reasons to pursue metastable structures within these materials. We hypothesize the synthesis of new permanent magnet can be achieved through the incorporation of orbital angular momentum from diamagnetic heavy elements. Compounds in this family are commonly not thermodynamic phases. Developing and understanding new superconductors necessitates the ability to synthesize a range of elemental compositions of a given structure type, regardless of thermodynamic phase stability. Most traditional solid-state reactions will produce the thermodynamically favored product; therefore we will seek alternative synthetic methods designed to access kinetic or metastable phases. Note that while kinetic phases are not the thermodynamic minimum, they are frequently nearly indefinitely stable once isolated, diamond being a common example of a metastable phases, which displays an extremely slow decay. Herein, we propose three synthetic approaches to access metastable materials designed for superconductivity or magnetism and the characterization of these compounds.