Cholesteric pitch-transitions induced by a magnetic field in a sample containing incomplete number of pitches

Ioannis Lelidis, Giovanni Barbero 2 , and Antonio Scarfone 3
  • 1 Solid State Section, Department of Physics, University of Athens, Panepistimiopolis, Zografos, Athens, 157 84, Greece
  • 2 Department of Applied Science and Technology, Politecnico di Torino, Corso Duca degli Abruzzi 24, 10129, Torino, Italia
  • 3 ISC-CNR, Istituto dei Sistemi Complessi — Consiglio Nazionale delle Ricerche, c/o Department of Applied Science and Technology, Politecnico di Torino, Corso Duca degli Abruzzi 24, 10129, Torino, Italia

Abstract

We investigate the pitch transitions induced by an external bulk field in a Cholesteric Liquid Crystal slab of finite thickness ℓ that contains an incomplete number of π-twists. The analysis is performed for a magnetic field that is (i) perpendicular to the helical axis, and (ii) tilted with respect to one of the easy directions imposed by planar and rigid boundary conditions. For finite ℓ we obtain a cascade of transitions, where the bulk expels a half-pitch at a time with increasing field to avoid divergences in the elastic energy. The dependence of the threshold magnetic field inducing the expulsion on the easy axes twist angle δ is investigated for all the cascade of pitch transitions and in particular for the final one, corresponding to the Cholesteric-Nematic transition. In the ℓ → ∞ limit this dependence disappears and we reobtain the results of de Gennes for an infinite sample.

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  • [1] V. Fredericks, V. Zolina, Trans. Faraday Soc. 29, 919 (1933) http://dx.doi.org/10.1039/tf9332900919

  • [2] W. Helfrich, Appl. Phys. Lett. 17, 531 (1970) http://dx.doi.org/10.1063/1.1653297

  • [3] J.P. Hurault, J. Chem. Phys. 59, 2068 (1973) http://dx.doi.org/10.1063/1.1680293

  • [4] I. Lelidis, M. Nobili, G. Durand, Phys. Rev. E 48, 3818 (1993) http://dx.doi.org/10.1103/PhysRevE.48.3818

  • [5] I. Lelidis, Phys. Rev. Lett. 86, 1267 (2001) http://dx.doi.org/10.1103/PhysRevLett.86.1267

  • [6] P.G. de Gennes, J. Prost, The Physics of Liquid Crystals (Clarendon Press, Oxford, 1993)

  • [7] L.M. Blinov, Structure and Properties of Liquid Crystals (Springer, 2001)

  • [8] M. Kleman, O.D. Lavrentovich, Soft Matter Physics: An Introduction (Springer, 2002)

  • [9] P. Seng, Phys. Rev. Lett. 37, 1059 (1976) http://dx.doi.org/10.1103/PhysRevLett.37.1059

  • [10] T.J. Sluckin, A. Poniewierski, In: Fluid Interfacial Phenomena, edited by C.A. Croxton, 215 (John Wiley, Chichester, 1986)

  • [11] T.J. Sluckin, Physica A 213, 105 (1995) http://dx.doi.org/10.1016/0378-4371(94)00151-I

  • [12] G. Barbero, L.R. Evangelista, An Elementary Course on the Continuum Theory for Nematic Liquid Crystals (World Scientific, 2001)

  • [13] I. Lelidis, P. Galatola, Phys. Rev. E 66, 10701 (2002) http://dx.doi.org/10.1103/PhysRevE.66.010701

  • [14] P.G. de Gennes, Solid State Commun. 6, 163 (1968) http://dx.doi.org/10.1016/0038-1098(68)90024-0

  • [15] R.B. Meyer, Appl. Phys. Lett. 12, 281 (1968) http://dx.doi.org/10.1063/1.1651992

  • [16] G. Durand, L. Leger, I. Rondelez, M. Veyssie, Phys. Rev. Lett. 22, 227 (1969) http://dx.doi.org/10.1103/PhysRevLett.22.227

  • [17] R.B. Meyer, Appl. Phys. Lett. 14, 208 (1969) http://dx.doi.org/10.1063/1.1652780

  • [18] R. Dreher, Solid State Commun. 13, 1571 (1973) http://dx.doi.org/10.1016/0038-1098(73)90239-1

  • [19] P.J. Kedney, I.W. Stewart, Continuum. Mech. Thermodyn. 6, 141 (1994) http://dx.doi.org/10.1007/BF01140895

  • [20] V.A. Belyakov, JETP Lett. 76, 88 (2002) http://dx.doi.org/10.1134/1.1510064

  • [21] S.V. Belyaev, L.M. Blinov, JETP Lett. 30, 99 (1979)

  • [22] E. Niggemann, H. Stegemeyer, Liq. Cryst. 5, 739 (1989) http://dx.doi.org/10.1080/02678298908045424

  • [23] P. Oswald, J. Baudry, S. Pirkl, Phy. Rep. 337, 67 (2000) http://dx.doi.org/10.1016/S0370-1573(00)00056-9

  • [24] A.M. Scarfone, I. Lelidis, G. Barbero, Phys. Rev. E 84, 021708 (2011) http://dx.doi.org/10.1103/PhysRevE.84.021708

  • [25] M. Abramowitz, I.A. Stegun, Handbook of mathematical function, (Dover pubblication, Inc. New York, 1970)

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