Projects / Programmes source: ARIS

Liquid Magnets: fundamental studies of ferromagnetic order in liquids

Research activity

Code Science Field Subfield
1.02.01  Natural sciences and mathematics  Physics  Physics of condesed matter 

Code Science Field
1.03  Natural Sciences  Physical sciences 
ferrofluids, colloidal nematic, liquid crystals, magnetic soft matter
Evaluation (rules)
source: COBISS
Data for the last 5 years (citations for the last 10 years) on April 20, 2024; A3 for period 2018-2022
Data for ARIS tenders ( 04.04.2019 – Programme tender, archive )
Database Linked records Citations Pure citations Average pure citations
WoS  351  7,170  6,026  17.17 
Scopus  353  7,654  6,438  18.24 
Researchers (8)
no. Code Name and surname Research area Role Period No. of publicationsNo. of publications
1.  10373  PhD Irena Drevenšek Olenik  Physics  Researcher  2020 - 2024  575 
2.  52045  PhD Žiga Gregorin  Physics  Junior researcher  2020 - 2022  32 
3.  50589  PhD Patricija Hribar Boštjančič  Physics  Researcher  2020 - 2022  62 
4.  15148  PhD Darja Lisjak  Materials science and technology  Researcher  2020 - 2024  412 
5.  55006  Peter Medle Rupnik    Researcher  2021 - 2024  25 
6.  14079  PhD Alenka Mertelj  Physics  Researcher  2020 - 2024  292 
7.  39399  PhD Nerea Sebastian Ugarteche  Physics  Head  2020 - 2024  120 
8.  18275  PhD Mojca Vilfan  Physics  Researcher  2020 - 2024  159 
Organisations (1)
no. Code Research organisation City Registration number No. of publicationsNo. of publications
1.  0106  Jožef Stefan Institute  Ljubljana  5051606000  90,682 
Fundamental research on magnetic materials is of great and expanding interest due to the growing demand of novel magnetic functional materials for technological advances. Among them, magnetic responsive liquids are very interesting for a wide range of novel applications in the field of energy harvesting, magneto-mechanical actuation and pumping, light control by magnetic fields, or magnetic field sensing. Classical ferrofluids, i.e. colloidal suspensions of ferromagnetic nanoparticles dispersed in isotropic solvent, are despite their name, paramagnetic, since the dispersed particles have random orientations in the absence of external magnetic. Experimental realization of truly ferromagnetic ferrofluids, retaining magnetic ordering under no external fields, has been a long-standing challenge, which was only recently overcome by the groundbreaking research of some of the team members of the proposed project, where suspensions of scandium substituted barium hexaferrite nanoparticles in n-butanol show not only nematic ordering, but also spontaneous ferromagnetic fluid ordering. Such liquid magnets have opened up the possibility to experimentally study a completely new set of exciting fundamental physical phenomena lying between our understanding of solid magnets and paramagnetic ferrofluids. In the present project, we aim to conduct a fundamental and thorough study of these novel magnet materials, with the final goal of creating a comprehensive framework for developing the field of ferromagnetisim in fluids. We will start by the optimization and development of these novel liquid magnet materials, by tuning the different parameters: the steric and magnetic interactions, by control of the particle size distribution/magnetization, and the electrostatic interactions by means of surfactant concentration. By full characterization of their physical properties (i.e. order parameter, birefringence, saturation magnetization, viscosities, diffusion coefficients, AC susceptibility), we aim to develop materials with tailored properties, in which response times to external fields are minimized while magnetic and optical responses are maximized. Structural analysis by means of SAXS, SANS, and SANSPOL should additionally provide insights into the spatial interparticle correlations and magnetic correlations. Remarkably, uniform magnetic domains spanning up to few millimeters can be systematically annealed by confinement in capillaries, forming textbook closure magnetic domain structures. Being fluid, the viscosities and orientational elastic constants will strongly influence the structure, stability, and formation time of the domains, resulting in a rich hierarchy of structures, where the domain walls can easily bend. We aim to generate in-depth understanding of such magnetic domain formation mechanisms under simple and customized confinement and to assess the stability of domains under external static fields, by combining experimental observations and the development of a macroscopic model based on the Landau-de-Gennes approach. By achievement of ultrasensitive monodomain samples, we will explore the possibilities of magnetic signal propagation by actuation with local static and time dependent microtesla magnetic fields. Finally, we will investigate the induction of flow by application of external time dependent magnetic fields, resulting from the strong coupling between flow and magnetization, with the final aim to realize a non-tactile microfluidic pumping system. The proposed liquid magnets are responsive to magnetic fields orders of magnitude smaller than those usually reported for ferrofluids, and therefore constitute great progress in material development for novel applications of magnetic liquids. It is expected that the generated knowledge derived from these studies will form the basis for the potential exploitation of these new liquid magnets in technological applications.
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