物理学科談話会：　Macroscopic properties of ferromagnetic nematics

日程: 2019年8月29日(木)　16:00～17:30
場所: 後楽園キャンパス３号館３階　3300号教室

日程: 2019年8月29日(木)　16:00～17:30

場所: 後楽園キャンパス３号館３階　3300号教室

講演者

Helmut R. Brand 氏

Department of Physics, University of Bayreuth Bayreuth, Germany

内容

Already more than 4 decades ago the possibility of ferromagnetic nematic liquid crystals has been postulated [1] by combining ferromagnetic nanoparticles with a nematic solvent. First experiments along these ideas were carried out immediately [2], giving rise to ferronematics with no spontaneous magnetization. Only a few years ago [3], with the development of suitably well-characterized magnetic nanoparticles, truly ferromagnetic nematics could be synthesized and analyzed thus establishing the first multiferroic liquid system. The static properties including magneto-optic and converse magnetoelectric effects were demonstrated [4]. Quite recently the study of the dynamics of truly ferromagnetic nematic liquid crystals properties has started [5]. It was demonstrated in [5] that a dissipative cross- coupling between the two order parameters [6], magnetization and director, is essential to account for the dynamic experimental results quantitatively. Recent developments in the dynamic domain include investigations of the light scattering behavior [7] as well as the coupling to flow including shear flows [8], the analog of the Miesowicz viscosities familiar from usual nematic liquid crystals [8] and the influence of tetrahedral order [9].

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[2] J. Rault, P.E. Cladis, and J.-P. Burger, Phys. Lett. A 32, 199 (1970).

[3] A. Mertelj, D. Lisjak, M. Drofenik, and M. Copic, Nature 504, 237 (2013).

[4] A. Mertelj, N. Osterman, D. Lisjak, and M. Copic, Soft Matter 10, 9065 (2014).

[5] T. Potisk et al., Phys. Rev. Lett. 119, 097802 (2017).

[6] E. Jarkova, H. Pleiner, H.-W. Mueller and H.R. Brand, J. Chem. Phys.

118, 2422 (2003).

[7] T. Potisk et al., Phys. Rev. E 97, 012701 (2018).

[8] T. Potisk, H. Pleiner, D. Svensek and H.R. Brand, Phys. Rev. E 97,

042705 (2018).

[9] T. Potisk, H. Pleiner, and H.R. Brand, Phys. Rev. E 98, 042703 (2018).

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