| We present a novel study on the effect of a magnetic field applied on a binary mixture doped with magnetic nanoparticles close to its demixing transition. Turbidity measurements in the Faraday configuration show that the effect of applying an external field produces changes in the critical opalescence of the mixture that allow to track an aggregation produced by critical Casimir forces and a reversible aggregation due to the formation of chain like flocks in response to the external magnetic field. The observation of a crossover of the aggregation curves trough optical signals is interpreted as the evolution from low to high power dispersion nuclei due to an increase in the radius of the condensation seed brought about by Casimir or magnetic interactions. Finally, evidences of an enhanced magnetocaloric effect due to the coupling between mixing and ordering phase transitions are presented which opens up a non solid state approach of designing refrigerating cycles and devices. |
|