Abstract

Earlier we observed a movement of the front of ions in the bulk of an ordered LC sample across which the driven voltage was applied [1]. This movement looked as waving zigzag curvatures in the pattern of interference strips. It was shown that behind the movable front of ions, the LC volume was getting charged. The author has found out that, in his pioneer experiments made in 1974, he observed the similar electrooptical phenomena on a single crystal of niobate-strontium-barium (NBS). Just after applying driving voltage (in a crossed electrical field crystal sample geometry) a system of curved interference strips is arising, which is evolving for the time period of about ten minutes at the driven voltage being kept constant. The evolution of the interference stripes pattern near positive, negative electrodes and in middle part of sample occurs in some different ways. At the end of evolution the system of strips disappears and the sample becomes practically homogeneous. The described process can be observed only once at the first applying of the driving voltage. This process is caused by redistribution of charges frozen at the crystallization and which are having an opportunity of the recombination at the first applying of the driving voltage. The obtained results are discussed with the possible applying the given experimental technique for solid and LCs parameters studying.

Highlights

  • During some time we were engaged in studing movement of charged carriers in ordered bulk samples of nematic liquid crystals (LC)

  • When the driving voltage was applied to the LC sample, waving zigzag curvatures in the pattern of interference strips were induced near the positive electrode, the front of which moved to the negative one with the velocity of about 6 m/sec

  • We have shown that the LC volume behind the waving front has a surplus volumetric charge, whereas the LC volume before the waving front was electrically neutral

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Summary

Introduction

During some time we were engaged in studing movement of charged carriers in ordered bulk samples of nematic liquid crystals (LC). Under the driving voltage applied the sample texture looked like waving zigzag curvatures in the pattern of interference. Under the driving voltage applied the sample texture looked like waving zigzag curvatures in the pattern of interference strips. These phenomena are the result of local distortions of the external electrical field and of hydrodynamical stream flows both caused by moveable (driven) ions. The described above processes can be repeated unlimited number of times provided that the volumetric charge is allowed completely to relax (i.e. the experiments may be repeated in the period of time not less than 12 hours). We had decided to repeat the described above experiments with the sample of NBS-crystal

Investigations of Solid Crystals
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