Conventional and inverse barocaloric effects around triple points in ferroelastics (NH4)(3)NbOF6 and (NH4)(3)TiOF5

Gorev, M. V.; Bogdanov, E. V.; Flerov, I. N. SCRIPTA MATERIALIA, 139 53-57; 10.1016/j.scriptamat.2017.06.022 OCT 2017

We report the conventional and inverse barocaloric effect (BCE) in ferroelastics (NH₄)₃NbOF₆ and (NH₄)₃TiOF₅. We found a rich set of the structural phase transitions and triple points on the T − p phase diagrams. Extensive and intensive BCE near some transformations and around triple points in both crystals are outstanding (|∆ S_BCE^max | = 30–100 J/kg·K; |∆ T_AD^max | = 4–22 K) and can be achieved at low pressure 0.01–0.60 GPa.