Supporting data for "Metallic local-moment magnetocalorics, a new route to cryogenic refrigeration"

Data underlying the figures shown in the publication 'Metallic local-moment magnetocalorics, a new route to cryogenic refrigeration'. Abstract: Commercial adiabatic demagnetisation refrigerators still employ the same hydrated salts that were first introduced over 85 years ago. The inherent limitations of these insulating magne- tocalorics – poor thermal conductivity at sub-Kelvin temperatures, low entropy density, corrosive- ness – can be overcome by a new generation of rare-earth based metallic magnetocalorics. Here, we present the metallic magnetocaloric YbNi1.6Sn as an attractive alternative to conventional re- frigerants. YbNi1.6Sn retains high entropy into the 100mK regime and avoids the noble metal constituents of alternative refrigerants. Demagnetisation tests demonstrate that YbNi1.6Sn enables economical and durable alternatives to traditional cooling devices for temperatures reaching below 120mK. We find that the magnetocaloric properties of this material are facilitated by unusually small Kondo and RKKY interactions, which position YbNi1.6Sn in the extreme local moment limit on the generalised Kondo lattice phase diagram.