Barocaloric effect:: The use of pressure for magnetic cooling in Ce3Pd20Ge6

The barocaloric effect found in many rare-earth compounds opens the way to novel magnetic refrigeration techniques which are rather based on the application of external pressure than on the application of large external magnetic fields as needed for cooling by the magnetocaloric effect. Here we report on the first observation of this effect in a heavy-fermion system, namely the Kondo lattice compound Ce3Pd20Ge6. Upon isothermal application of uniaxial pressure the compound lowers the magnetic entropy, subsequent adiabatic release of the pressure leads to a cooling by as much as -0.75 K per 0.3 GPa pressure release at 4.4 K. Based on entropy considerations the observed cooling effect can be explained by an increase of the Kondo temperature and by a structurally induced splitting of the Gamma(8) ground-state quartet upon uniaxial pressure. (C) 2002 American Institute of Physics.