Giant Reversible Barocaloric Effect with Low Hysteresis in Antiperovskite PdNMn 3 Compound

Barocaloric (BC) refrigeration is a new type of clean and energy-efficiency refrigeration technology. However, the giant and colossal BC effects are mainly based on the first-order phase transitions, leading to the unfavorable hysteresis. Here we report the giant BC effect along with weak hysteresis at the antiferromagnetic (AFM) to paramagnetic (PM) phase transition (TN =283 K) in antiperovskite PdNMn 3 compound. The reversible isothermal entropy change reaches 28.3 J kg-1K-1 under 290 MPa. The hysteresis is only about 2 K, which is associated with a small volumetric change ΔV/V at TN (~0.2%). The magnetic entropy is proposed to mainly contribute to the entropy change at TN , which compensates for the reduced lattice contribution due to the small ΔV/V . Our result demonstrates the possibility of realizing giant BC effect together with weak hysteresis in materials where both crystallographic and non-crystallographic entropy changes cooperate at the first-order phase transition (FOPT).