The study of materials with giant caloric effect (reversible thermal changes induced by an external stimulus), is currently a hot topic in Materials Science since they are the best-placed candidates to develop new efficient and environmentally friendly refrigerators that must replace current devices, which feature low efficiency and use hazardous fluids.
Extensive research has shown that the caloric effects in solid-state materials can be triggered by various external stimuli: magnetic field (magnetocaloric effect), electric field (electrocaloric effect), uniaxial stress (elastocaloric effect), hydrostatic pressure (barocaloric effect) or a combination of different stresses.
While magnetocaloric and electrocaloric effects require magnetically or electrically polarized materials, barocaloric effects can be found in any compressible material, which make them more interesting.
There is therefore a need to find out caloric materials exhibiting both large isothermal entropy and adiabatic temperature changes, for which these changes are reproducible upon cyclic application and removal of hydrostatic pressure.
A research, recently published in Advanced Materials, studies the barocaloric properties of Fe3(bntrz)6(tcnset)6, a molecular material that contains a metal complex that undergoes an abrupt spin-state switching (spin-crossover transition) close to room temperature. The work was carried out by a team from the Universitat de Barcelona (Spain), the Universitat Politècnica de Catalunya (Spain), the Florida State University (USA), the University of Science and Technology Beijing (China) and the Ankara University (Turkey), in collaboration with the ALBA Synchrotron.
Read more on the ALBA website