V reviji Small je izšel članek “Spontaneous chiral symmetry breaking and lane formation in ferromagnetic ferrofluids”, v katerem raziskovalci z Odseka za kompleksno snov s soavtorji opisujejo opazovanje spontanega zloma kiralne simetrije v feromagnetnih ferofluidih. To so suspenzije magnetnih nanoploščic v izotropni tekočini, ki se pri dovolj velikih koncentracijah uredijo in se zato na zunanje magnetno polje odzivajo kot feromagnet. V izmeničnem zunanjem magnetnem polju pod polarizacijskim mikroskopom pri določenih pogojih v tekočini opazimo progasto strukturo, ki jo pojasnimo z nastankom magnetnih domen. Spontani zlom simetrije v vzorcu vodi do vrtenja delcev in posledično do nastanka tekočinskih tokov, ki kljub homogenemu zunanjemu polju v sosednjih progah poteka izmenično v nasprotnih smereh. Spontano izoblikovani mikrofluidični kanalčki, v katerih vrtenje nanodelcev poganja tekočinski tok, so osnova brezkanalne mikrofluidike.

Researchers from the Department of Complex Matter and co-authors have published the paper “Spontaneous chiral symmetry breaking and lane formation in ferromagnetic ferrofluids” in the journal Small. Ferromagnetic ferrofluids are suspensions of magnetic nanoplatelets in isotropic fluids, which at sufficiently high particle concentrations exhibit ferromagnetic response to external magnetic fields. Exposed to an oscillating magnetic field, under certain conditions, a striped structure is observed under polarising microscope, which can be explained as the formation of magnetic domains. Spontaneous chiral symmetry breaking in the sample leads to nanoparticle rotation and consequently to the generation of fluid flow which, despite the uniformity of the external field, flows in opposite directions in neighboring stripes. Spontaneously formed microfluidic channels, in which the fluid flow is driven by the nanoparticle rotation, are the basis for future tubeless microfluidic applications.

Small:  https://onlinelibrary.wiley.com/doi/10.1002/smll.202304387