Rare-earth Engineering of the Magnetocaloric Effect in RMn6Sn6

We present a comprehensive study of the magnetocaloric effect (MCE) in a family of kagome magnets with formula RMn6Sn6 (R=Tb, Ho, Er, and Lu). These materials have a small rare-earth content and tunable magnetic ordering, hence they provide a venue to study the fundamentals of the MCE. We examine the effect of different types of order (ferromagnetic, ferrimagnetic, and antiferromagnetic) and the presence of a metamagnetic transition on the MCE. We extend the study to a high-entropy rare-earth alloys of the family, and conclude with several guidelines for enhancing the MCE in tunable magnetic materials with a small rare-earth content.