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Sebastian N, Lisjak D, Čopič M, Buchnev O, Mertelj A. Comparison of dynamic behavior of ferroelectric and ferromagnetic nematic suspensions. J Mol Liq 2018. [DOI: 10.1016/j.molliq.2017.11.157] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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Affiliation(s)
- M. Čopič
- Nuclear Institute Josef Stefan, Ljubljana, Yugoslavia
| | - T. Kalin
- Nuclear Institute Josef Stefan, Ljubljana, Yugoslavia
| | - G. Pregl
- Nuclear Institute Josef Stefan, Ljubljana, Yugoslavia
| | - F. Žerdin
- Nuclear Institute Josef Stefan, Ljubljana, Yugoslavia
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Shuai M, Klittnick A, Shen Y, Smith GP, Tuchband MR, Zhu C, Petschek RG, Mertelj A, Lisjak D, Čopič M, Maclennan JE, Glaser MA, Clark NA. Spontaneous liquid crystal and ferromagnetic ordering of colloidal magnetic nanoplates. Nat Commun 2016; 7:10394. [PMID: 26817823 PMCID: PMC4738347 DOI: 10.1038/ncomms10394] [Citation(s) in RCA: 78] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2015] [Accepted: 12/08/2015] [Indexed: 11/18/2022] Open
Abstract
Ferrofluids are familiar as colloidal suspensions of ferromagnetic nanoparticles in aqueous or organic solvents. The dispersed particles are randomly oriented but their moments become aligned if a magnetic field is applied, producing a variety of exotic and useful magnetomechanical effects. A longstanding interest and challenge has been to make such suspensions macroscopically ferromagnetic, that is having uniform magnetic alignment in the absence of a field. Here we report a fluid suspension of magnetic nanoplates that spontaneously aligns into an equilibrium nematic liquid crystal phase that is also macroscopically ferromagnetic. Its zero-field magnetization produces distinctive magnetic self-interaction effects, including liquid crystal textures of fluid block domains arranged in closed flux loops, and makes this phase highly sensitive, with it dramatically changing shape even in the Earth's magnetic field. Ferromagnetism has been known as a material property of solids since the time of the ancient Greeks. Here, Shuai et al. report that magnetic nanoplates suspended in a simple solvent can spontaneously align to form a ferromagnetic liquid, capable of both producing and sensing magnetic fields.
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Affiliation(s)
- M Shuai
- Department of Physics and Soft Materials Research Center, University of Colorado, Boulder, Colorado 80309, USA
| | - A Klittnick
- Department of Physics and Soft Materials Research Center, University of Colorado, Boulder, Colorado 80309, USA
| | - Y Shen
- Department of Physics and Soft Materials Research Center, University of Colorado, Boulder, Colorado 80309, USA
| | - G P Smith
- Department of Physics and Soft Materials Research Center, University of Colorado, Boulder, Colorado 80309, USA
| | - M R Tuchband
- Department of Physics and Soft Materials Research Center, University of Colorado, Boulder, Colorado 80309, USA
| | - C Zhu
- Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - R G Petschek
- Department of Physics, Case Western Reserve University, Cleveland, Ohio 44106, USA
| | - A Mertelj
- Jozef Stefan Institute, SI-1000 Ljubljana, Slovenia
| | - D Lisjak
- Jozef Stefan Institute, SI-1000 Ljubljana, Slovenia
| | - M Čopič
- Jozef Stefan Institute, SI-1000 Ljubljana, Slovenia.,Faculty of Mathematics and Physics, University of Ljubljana, SI-1000 Ljubljana, Slovenia
| | - J E Maclennan
- Department of Physics and Soft Materials Research Center, University of Colorado, Boulder, Colorado 80309, USA
| | - M A Glaser
- Department of Physics and Soft Materials Research Center, University of Colorado, Boulder, Colorado 80309, USA
| | - N A Clark
- Department of Physics and Soft Materials Research Center, University of Colorado, Boulder, Colorado 80309, USA
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Adlem K, Čopič M, Luckhurst GR, Mertelj A, Parri O, Richardson RM, Snow BD, Timimi BA, Tuffin RP, Wilkes D. Chemically induced twist-bend nematic liquid crystals, liquid crystal dimers, and negative elastic constants. Phys Rev E Stat Nonlin Soft Matter Phys 2013; 88:022503. [PMID: 24032852 DOI: 10.1103/physreve.88.022503] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/03/2013] [Indexed: 06/02/2023]
Abstract
Here we report the chemical induction of the twist-bend nematic phase in a nematic mixture of ether-linked liquid crystal dimers by the addition of a dimer with methylene links; all dimers have an odd number of groups in the spacer connecting the two mesogenic groups. The twist-bend phase has been identified from its optical texture and x-ray scattering pattern as well as NMR spectroscopy, which demonstrates the phase chirality. Theory predicts that the key macroscopic property required for the stability of this chiral phase formed from achiral molecules is for the bend elastic constant to tend to be negative; in addition the twist elastic constant should be smaller than half the splay elastic constant. To test these important aspects of the prediction we have measured the bend and splay elastic constants in the nematic phase preceding the twist-bend nematic using the classic Frederiks methodology and all three elastic constants employing the dynamic light scattering approach. Our results show that, unlike the splay, the bend elastic constant is small and decreases significantly as the transition to the induced twist-bend nematic phase is approached, but then exhibits unexpected behavior prior to the phase transition.
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Affiliation(s)
- K Adlem
- Merck Chemicals Ltd., Chilworth Technical Centre, University Parkway, Southampton SO16 7QD, United Kingdom
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Affiliation(s)
- A. Mertelj
- a J. Stefan Institute , Jamova 39, 1001 , Ljubljana , Slovenia
| | - M. Čopič
- a J. Stefan Institute , Jamova 39, 1001 , Ljubljana , Slovenia
- b Department of Physics , University of Ljubljana , 1000 , Ljubljana , Slovenia
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A.Mrzel,, A.Mertelj,, Omerzu A, Čopič M, Mihailovic D. Investigation of Encapsulation and Solvatochromism of Fullerenes in Binary Solvent Mixtures. J Phys Chem B 1999. [DOI: 10.1021/jp992637e] [Citation(s) in RCA: 56] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- A.Mrzel,
- Jozef Stefan Institute, Jamova 39, 1000 Ljubljana, Slovenia, and Faculty of Mathematics and Physics, University of Ljubljana, 1000 Ljubljana, Slovenia
| | - A.Mertelj,
- Jozef Stefan Institute, Jamova 39, 1000 Ljubljana, Slovenia, and Faculty of Mathematics and Physics, University of Ljubljana, 1000 Ljubljana, Slovenia
| | - A. Omerzu
- Jozef Stefan Institute, Jamova 39, 1000 Ljubljana, Slovenia, and Faculty of Mathematics and Physics, University of Ljubljana, 1000 Ljubljana, Slovenia
| | - M. Čopič
- Jozef Stefan Institute, Jamova 39, 1000 Ljubljana, Slovenia, and Faculty of Mathematics and Physics, University of Ljubljana, 1000 Ljubljana, Slovenia
| | - D. Mihailovic
- Jozef Stefan Institute, Jamova 39, 1000 Ljubljana, Slovenia, and Faculty of Mathematics and Physics, University of Ljubljana, 1000 Ljubljana, Slovenia
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Marchon B, Pasquier B, Le Calve N, Novak A, Čopič M, Zgonik M, Fox D, Lavrenčič BB. Infrared, Raman, and Brillouin spectra of CsH2PO4. J Chem Phys 1981. [DOI: 10.1063/1.440911] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
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