  We report on the magnetocaloric properties of two molecule-based
hexacyanochromate Prussian blue analogs, nominally CsNi[Cr(CN)_6](H_2O) and
Cr_3[Cr(CN)_6]_2x12(H_2O). The former orders ferromagnetically below Tc=90 K,
whereas the latter is a ferrimagnet below Tc=230 K. For both, we find
significantly large magnetic entropy changes DSm associated to the magnetic
phase transitions. Notably, our studies represent the first attempt to look at
molecule-based materials in terms of the magnetocaloric effect for temperatures
well above the liquid helium range.

Materials Science