Cooling by adiabatic (de)pressurization - The barocaloric effect

The barocaloric effect reflects a new cooling principle at low temperatures without the need of liquefied gases nor magnetic fields as used in other c ooling techniques. A pressure induced structural and/or magnetic phase tran sition is used to obtain a significant change in the system's entropy which leads to its cooling if done adiabatically. The effect is illustrated for the two rare earth compounds Pr1-xLaxNiO3 and Ce-x(La,Y)(1-x)Sb using a str uctural and a magnetic phase transition, respectively. In situ experiments on Ce-x(La,Y)(1-x)Sb are presented and reveal a cooling rate of up to 2 K p er 0.5 GPa pressure change at working temperatures below 20 K for x=l and u p to 0.42 K per 0.24 GPa for x=0.85 at around 10 K.