We concentrate on research of ferromagnetic liquid crystals. Starting with synthesis of hexagonal barium hexaferrite nanoplatelets and their functionalisation with dendrimers, we observe stable suspensions in both nematic and cholesteric liquid crystal. Ferromagnetic order appears as a result of a combination of elastic and magnetic interactions. The materials are further studied for their physical properties, such as magneto-optic response in external magnetic field and appearance of diverse field-controlled structures.

Magnetic particles in isotropic suspensions are being studied and we observe that at high enough volume fractions, ferromagnetic nematic ordering of the platelets appears, leading to a ferromagnetic ferrofluid.

Research also includes studies of magneto-active elastomers, which exhibit magnetically tunable surface roughness.

Selected references:

MERTELJ, Alenka, LISJAK, Darja, DROFENIK, Mihael, ČOPIČ, Martin. Ferromagnetism in suspensions of magnetic platelets in liquid crystal. Nature: the international weekly journal of science, ISSN 0028-0836. [Print ed.], 2013, vol. 504, no. 7479, str. 237-241, doi: 10.1038/nature12863.

LISJAK, Darja, MERTELJ, Alenka. Anisotropic magnetic nanoparticles : a review of their properties, syntheses and potential applications. Progress in Materials Science, ISSN 0079-6425. [Print ed.], 2018, vol. 95, str. 286-328, doi: 10.1016/j.pmatsci.2018.03.003.

HRIBAR, Patricija, TOMŠIČ, Matija, JAMNIK, Andrej, LISJAK, Darja, MERTELJ, Alenka. Electrostatic interactions between barium hexaferrite nanoplatelets in alcohol suspensions. The journal of physical chemistry. C, Nanomaterials and interfaces, ISSN 1932-7447, [in press] 2019, 8 str., doi: 10.1021/acs.jpcc.9b07455.

MERTELJ, Alenka, LAMPRET, Borut, LISJAK, Darja, KLEPP, Jürgen, KOHLBRECHER, J., ČOPIČ, Martin. Evolution of nematic and ferromagnetic ordering in suspensions of magnetic nanoplatelets. Soft matter, ISSN 1744-6848, 2019, vol. 15, no. 27, str. 5412-5420, doi: 10.1039/C9SM00949C.

SHUAI, M., MERTELJ, Alenka, LISJAK, Darja, ČOPIČ, Martin, et al. Spontaneous liquid crystal and ferromagnetic ordering of colloidal magnetic nanoplate. Nature communications, ISSN 2041-1723, 2016, vol. 7, str. 10394-1- 10394-8, doi: 10.1038/ncomms10394.

FERK, Gregor, KRAJNC, Peter, HAMLER, Anton, MERTELJ, Alenka, CEBOLLADA, Federico, DROFENIK, Mihael, LISJAK, Darja. Monolithic magneto-optical nanocomposites of barium hexaferrite platelets in PMMA. Scientific reports, ISSN 2045-2322, jun. 2015, vol. 5, str. 11395-1-11395-8, doi: 10.1038/srep11395.

MEDLE RUPNIK, Peter, LISJAK, Darja, ČOPIČ, Martin, ČOPAR, Simon, MERTELJ, Alenka. Field-controlled structures in ferromagnetic cholesteric liquid crystals. Science advances, ISSN 2375-2548, 2017, vol. 3, no. 10, str. e1701336-1-e1701336-11, doi: 10.1126/sciadv.1701336.

POTISK, Tilen, SVENŠEK, Daniel, BRAND, Helmut R., PLEINER, Harald, LISJAK, Darja, OSTERMAN, Natan, MERTELJ, Alenka. Dynamic magneto-optic coupling in a ferromagnetic nematic liquid crystal. Physical review letters, ISSN 0031-9007. [Print ed.], 2017, vol. 119, no. 9, str. 097802-1-097802-6, doi: 10.1103/PhysRevLett.119.097802.

SEBASTIÁN UGARTECHE, Nerea, OSTERMAN, Natan, LISJAK, Darja, ČOPIČ, Martin, MERTELJ, Alenka. Director reorientation dynamics of ferromagnetic nematic liquid crystals. Soft matter, ISSN 1744-683X, 2018, vol. 14, no. 35, str. 7180-7189, doi: 10.1039/C8SM01377B.

SEBASTIÁN UGARTECHE, Nerea, LISJAK, Darja, ČOPIČ, Martin, BUCHNEV, Oleksandr, MERTELJ, Alenka. Comparison of dynamic behavior of ferroelectric and ferromagnetic nematic suspensions. Journal of molecular liquids, ISSN 0167-7322. [Print ed.], 2018, vol. 267, str. 377-383, doi: 10.1016/j.molliq.2017.11.157.

GLAVAN, Gašper, KETTL, Wolfgang, BRUNHUBER, Alexander, SHAMONIN, Mikhail, DREVENŠEK OLENIK, Irena. Effect of material composition on tunable surface roughness of magnetoactive elastomers. Polymers, ISSN 2073-4360, 2019, vol. 11, art. no. 594, 13 str., ilustr., doi: 10.3390/polym11040594.