Giant electrocaloric effects in ferroelectric nanostructures with vortex domain structures

Electrocaloric effects of Bi4Ti3O12 (BIT) ferroelectric nanoparticles with vortex domain structures in a curled electric field are investigated using a phase field method. A large adiabatic temperature change (Delta T = 16.6 K) is observed in the BIT nanoparticles with the change in vorticity vector of the curled field Delta Q= 0.15 mV angstrom(-2) at 620 degrees C. This large DT is attributed to a large change in the toroidal moment which is associated with vortex domain structures in the nanoparticles under the curled electric field. These results indicate that ferroelectric nanostructures with vortex domain structures can be exploited for use in solid state refrigeration.