Local structure of a barocaloric framework material

Barocaloric materials, in which a large isothermal entropy change is associated with a pressure-induced phase transition, offer an alternative to vapour-compression techniques that rely on refrigerants that contribute to global warming and ozone depletion. The framework material TPrAMn(dca)3 has recently been shown to have a giant barocaloric effect, due to an order-disorder phase transition involving both the dca and TPrA ions. Crystallographic disorder of both ions in both the low- and high-symmetry phases makes structural characterisation extremely challenging, yet it is precisely this disorder that accounts for the material’s behaviour. The aim of this proposal is to achieve a quantitative understanding of this disorder by collecting high-resolution pair distribution functions from total scattering. This will complete the picture of the material’s local structure for the first time.