Reduced-Co Heusler Compound Revealed Through High Throughput Synthesis and Magnetic Screening

Heusler alloys (HAs) have peaked interests for their unique magnetic functionalities and highly tunable structures. Cobalt-based HAs, in particular, are remarkable for their robust magnetic moments and high magnetic ordering temperatures. However, with a limited supply, production concentrated in geopolitically unstable regions, and other key supply risks, cobalt is considered a critical material. This criticality underscores the need to explore alternative compositions, incorporating more abundant elements without compromising magnetic performance. In this study, we demonstrate the utility of a high-throughput approach leveraging Magneto-Optical Kerr Effect (MOKE) and Extended X-ray Absorption Fine Structure (EXAFS) fingerprinting in combination with combinatorial synthesis to identify Co-lean compositions in a thin film Co-Cr-Al Heusler alloy system. By screening for magnetism-defining attributes, such as coordination chemistry and phase, we identify promising compositions. Subsequently, we conduct high fidelity analyses on selected alloys to investigate the relationship between magnetism, composition, chemical short-range order, and structure. In doing so, we highlight a method to identify Co-lean HAs, providing insights into their magnetic properties and potential role as sustainable alternatives.