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Projects / Programmes source: ARIS

Electrically tunable ferromagnetic liquids

Research activity

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

Code Science Field
P002  Natural sciences and mathematics  Physics 

Code Science Field
1.03  Natural Sciences  Physical sciences 
Keywords
ferromagnetic liquid crystals, converse magnetoelectric effect, ferrofluids, ferromagnetism in liquids, soft matter
Evaluation (rules)
source: COBISS
Researchers (8)
no. Code Name and surname Research area Role Period No. of publicationsNo. of publications
1.  32783  PhD Sandra Gardonio  Materials science and technology  Researcher  2017 - 2020  82 
2.  26478  PhD Sašo Gyergyek  Materials science and technology  Researcher  2017 - 2020  292 
3.  15148  PhD Darja Lisjak  Materials science and technology  Researcher  2017 - 2020  414 
4.  10372  PhD Darko Makovec  Materials science and technology  Researcher  2017 - 2020  667 
5.  14079  PhD Alenka Mertelj  Physics  Head  2017 - 2020  294 
6.  25669  PhD Natan Osterman  Physics  Researcher  2017 - 2020  173 
7.  11991  PhD Matjaž Valant  Materials science and technology  Researcher  2017 - 2020  608 
8.  18275  PhD Mojca Vilfan  Physics  Researcher  2017 - 2020  159 
Organisations (2)
no. Code Research organisation City Registration number No. of publicationsNo. of publications
1.  0106  Jožef Stefan Institute  Ljubljana  5051606000  91,005 
2.  1540  University of Nova Gorica  Nova Gorica  5920884000  14,199 
Abstract
Magnetically and/or electrically responsive materials are crucial for a number of applications. An example of such soft materials are liquid crystals (LC), which exhibit strong electro-optic response and are widely used in modern displays, and ferrofluids which respond to magnetic field and are used as seals, semi-active dampers, positioning systems and transport agents. The advantage of soft materials over the solid ones is that they can be easily manipulated by small external fields. Ferromagnetic liquid crystals, which we discovered recently, are hybrids between the liquid crystals and the ferrofluids, and exhibit response to both, electric and small magnetic fields. They are suspensions of magnetic nanoplatelets in conventional liquid crystals. In these suspensions, in addition to the orientational order of the liquid crystal molecules, polar magnetic ordering of the nanoplatelets is present, which is reflected in macroscopic magnetization. Besides direct responses of the liquid crystal to electric field and the magnetization to magnetic field, the material also exhibits indirect responses. The LC orientation is affected by magnetic field, which is observed as magneto-optic response, and the magnetization responds to electric field. The indirect responses are a consequence of coupling between the orientational liquid-crystalline and magnetic orders. A microscopic origin of this coupling is in the interaction of the liquid crystal molecules with nanoplatelets surfaces, also called anchoring. In this project we will focus on the development and understanding of materials with large magnetization and strong response to electric field. So far realized ferromagnetic LC materials have either small magnetization and large response to electric field or large magnetization and small response to electric field. The aim of the proposed research is to design and fabricate materials that will combine both, and will be applicable in devices, where the control over magnetization is needed, e.g. nonreciprocal devices for information technology or variable sources of small magnetic field. We will follow two research directions. In the first, we will increase the concentration of dispersed magnetic nanoplatelets in nematic liquid crystals by the modification of (electro)steric barrier of the nanoplatelets and anchoring strength of LC molecules on the platelet surface. With this we will increase their magnetization, while retaining a strong response to electric field. In the second, we will develop the suspensions of magnetoelectric Janus nanoplatelets by decorating magnetic nanoplatelets with polar or charged organic molecules in such a way that they will exhibit also electric dipole moments. So we will be able to induce magnetization by an external electric field also in initially isotropic suspension, i.e., without the orientational (nematic or polar) order. This interdisciplinary project will be realized by the research groups with complementary knowledge, skills and equipment. The research group from Department for Complex Matter from Jožef Stefan Institute will cover physical characterization, modelling of the materials and the development of a fluidic device for the synthesis of the Janus platelets. The research group from Department for Materials Synthesis, also from Jožef Stefan Institute, will cover the colloidal and surface chemistry challenges related to the surface functionalization of nanoplatelets and the synthesis of magnetoelectric Janus particles. All chemical processes will be followed with specific chemical analyses, conducted by the third research group from University of Nova Gorica. For the development of new type of soft materials, i.e., electrically tunable magnetic liquids, new knowledge related to surface and colloidal chemistry, and soft matter physics will be generated, and new process for the synthesis of Janus particles will be established.
Significance for science
While ferromagnetism in solids is well known and new solid magnetic materials are being developed and studied constantly, ferromagnetic liquids are rare. Our recent realization of ferromagnetic liquid crystalline colloids, which exhibit ferromagnetic ordering at room temperature, paves the way for the development of new ferromagnetic liquids, which is one of the objectives of the proposed project. Our discovery has already opened opportunity to study unique phenomena related to ferromagnetism in liquid systems in several world-recognized research groups (e.g. University of Boulder, USA ; Osaka University, Japan). It is of crucial importance that also we continue research in this direction. The scientific and technological objectives of the proposed research are highly challenging and the novelty of the project results will be three-fold. (i) It will give new fundamental knowledge related to colloidal stabilization and physics of magnetoelectric liquids. First is of the utmost importance for the development of these materials, while the latter determines their performance in devices. (ii) We will fabricate new soft functional materials: a range of ferromagnetic nematic liquid crystals with enhanced magnetic properties and strong response to the electric field; and a suspension of magnetoelectric Janus particles, which will be a liquid analog of a solid multiferroic material. (iii) A new technology for selective functionalization of Janus platelets with various functional properties will be developed. Realization of the proposed objectives will open up possibilities for new research directions in soft matter physics, in particular fundamental studies of (i) the behavior of a liquid ferromagnetic phase and its topological structures, (ii) hydrodynamics and magneto/electro rheology of the new liquid materials, and (iii) their interaction with electromagnetic waves at GHz frequencies, where magnetic properties play a key role. The latter is particularly interesting for the applications in devices used in information technology. Additional research possibilities will arise also in the field of chemistry. Specifically, the new knowledge on colloidal stabilization of magnetic platelets can be exploited for any other (nano)particles. Consequently, we expect a long-term impact on the research in the colloidal and surface chemistry. Moreover, this knowledge will trigger development of the colloidal chemistry processing and assembling approaches for the fabrication of new hybrid functional materials. The new technology for the fabrication of Janus particles will pave the way toward more intense studies of Janus nanoparticles, which are now limited by very low synthesis yields. Knowing that Janus particles with their dual nature exhibit a wide range of interesting properties, we expect a high impact in this field. The interest in Janus particles arises also from a great variety of potential applications, which may be finally possible by the upscaling of the developed new technology.
Significance for the country
Although the proposed project is focused on solving fundamental problems in the fabrication and understanding of magnetoelectric liquids, the motivation for it lays in the development of new advanced materials, which are suitable for applications, e.g. in microwave devices, in microfluidics, as tunable sources of magnetic field, and for production of similar materials using new fundamental knowledge and technologies. The proposed materials have no counterpart in exiting materials, so new applications may emerge, after the properties of the material will be fully studied and understood. The aim of the project is to develop the synthesis and understanding of the behavior of the materials, which will form a basis for further progress of the material fabrication to reach the level, which would allow small-scale production. The company Nanos Scientificae d.o.o. (http://nanos-sci.com/), which was cofounded by a member of the project group, is a spin out company from J. Stefan Institute developing nanotechnology solutions based on magnetic nanoparticles and it is a perfect candidate for marketing and production of the material. Involvement of the researchers from Jožef Stefan Institute (JSI) in the development of liquid crystal based technologies for niche applications is well established. An example is the company Balder, Ltd., which was established as a spin-off company of JSI, and its R&D is still supported by the researchers from JSI, among others from the Department for Complex Matter. The new material will allow researchers at JSI and University of Nova Gorica (UNG) to develop the products, which will use the principles of LC technologies to control magnetization. The precise control of the magnetization can be exploited for example to manipulate electromagnetic waves in nonreciprocal devices in the information technology, or to generate well defined switchable magnetic fields for microfluidics applications, e.g., for magnetic micro-separation. As the devices will operate at low voltages, similarly as the LC components do, their energy consumption will be very low. These will open up a possibility for the collaboration with the partners from Slovenian industry to produce new-generation devices with a very high added value.
Most important scientific results Final report
Most important socioeconomically and culturally relevant results Interim report, final report
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