Magnetic field effects in nematic and smectic liquid crystals probed by time resolved observation of orientation relaxation of the spin probe

2018 ◽  
Vol 20 (27) ◽  
pp. 18340-18347 ◽  
Author(s):  
Alexey V. Bogdanov ◽  
Gleb I. Proniuk ◽  
Andrey Kh. Vorobiev
Keyword(s):  
Magnetic Field ◽  
Liquid Crystal ◽  
Spin Probe ◽  
Smectic Liquid Crystals ◽  
Magnetic Field Effects ◽  
Time Resolved ◽  
Smectic Phases ◽  
Orientation Relaxation ◽  
Kinetics Of ◽  
The Magnetic Field

The kinetics of reorientation of the liquid crystal HOPOOB in nematic and smectic phases in the magnetic field was studied by the spin probe technique.

Time Resolved Magnetic Field Effects as a Probe for Geminate Recombination

1976 ◽  
Vol 31 (5) ◽  
pp. 499-500 ◽  
Author(s):  
R. Haberkorn ◽  
M. E. Midiel-Beyerle
Keyword(s):  
Magnetic Field ◽  
Field Effect ◽  
Magnetic Field Effect ◽  
Theoretical Description ◽  
Transfer Reactions ◽  
Geminate Recombination ◽  
Magnetic Field Effects ◽  
Time Resolved ◽  
Transient Spectroscopy ◽  
The Magnetic Field

Abstract A theoretical description for the magnetic field dependence of geminate recombination as observed in transient spectroscopy of electron transfer reactions, is given and applications of this novel magnetic field effect are discussed.

Dynamics of a disc in a nematic liquid crystal

Soft Matter ◽  
2016 ◽  
Vol 12 (4) ◽  
pp. 1279-1294 ◽  
Author(s):  
Alena Antipova ◽  
Colin Denniston
Keyword(s):  
Magnetic Field ◽  
Liquid Crystal ◽  
Numerical Simulations ◽  
Nematic Liquid Crystal ◽  
Weak Magnetic Field ◽  
Angular Speed ◽  
The Magnetic Field

We explain the motion of a micron-sized ferromagnetic disc immersed in a nematic liquid crystal under the action of a weak magnetic field using numerical simulations. We show that the disc's behaviour can be controlled by the angular speed of the magnetic field and its magnitude.

INFLUENCE OF DIMENSIONALITY AND SURFACE ORDERING ON PHASE TRANSITIONS: STUDIES OF FREELY-SUSPENDED LIQUID-CRYSTAL FILMS

1994 ◽  
Vol 08 (22) ◽  
pp. 3051-3082 ◽  
Author(s):  
CHRISTIAN BAHR
Keyword(s):  
Phase Transitions ◽  
Liquid Crystal ◽  
Two Dimensions ◽  
Smectic Liquid Crystals ◽  
Liquid Crystal Films ◽  
Integral Number ◽  
Smectic Phases ◽  
Crystal Films ◽  
Freely Suspended ◽  
Freely Suspended Films

Freely-suspended films of smectic liquid crystals can be regarded as membranes consisting of a stack of an integral number of molecular (smectic) layers with the layer planes being parallel to the two free surfaces. Because of their variable thickness (between thousands and only two layers) and the large variety of phase transitions between different smectic phases, freely-suspended films are excellent systems to study the influence of the dimensional cross-over from three to two dimensions on phase transitions. Further, because the free surface of a liquid crystal has a strong ordering effect (contrary to solids which exhibit generally surface-induced disorder), freely-suspended films are well-suited for the study of the effect of enhanced surface order on phase transitions. A review of the corresponding experimental work is given.

scholarly journals LOCAL ORDER AND MAGNETIC FIELD EFFECTS ON THE ELECTRONIC PROPERTIES OF DISORDERED BINARY ALLOYS IN THE QUANTUM SITE PERCOLATION LIMIT

1999 ◽  
Vol 13 (32) ◽  
pp. 3861-3877
Author(s):  
D. F. DE MELLO ◽  
G. G. CABRERA
Keyword(s):  
Magnetic Field ◽  
Electronic Properties ◽  
Binary Alloys ◽  
Finite Size ◽  
Local Order ◽  
Destructive Interference ◽  
Magnetic Field Effects ◽  
Site Percolation ◽  
Field Effects ◽  
The Magnetic Field

Electronic properties of disordered binary alloys are studied via the calculation of the average Density of States (DOS) in two and three dimensions. We propose a new approximate scheme that allows for the inclusion of local order effects in finite geometries and extrapolates the behavior of infinite systems following finite-size scaling ideas. We particularly investigate the limit of the Quantum Site Percolation regime described by a tight-binding Hamiltonian. This limit was chosen to probe the role of short range order (SRO) properties under extreme conditions. The method is numerically highly efficient and asymptotically exact in important limits, predicting the correct DOS structure as a function of the SRO parameters. Magnetic field effects can also be included in our model to study the interplay of local order and the shifted quantum interference driven by the field. The average DOS is highly sensitive to changes in the SRO properties and striking effects are observed when a magnetic field is applied near the segregated regime. The new effects observed are twofold: there is a reduction of the band width and the formation of a gap in the middle of the band, both as a consequence of destructive interference of electronic paths and the loss of coherence for particular values of the magnetic field. The above phenomena are periodic in the magnetic flux. For other limits that imply strong localization, the magnetic field produces minor changes in the structure of the average DOS.

scholarly journals Precessing Ball Solitons in Kinetics of a Spin-Flop Phase Transition

2011 ◽  
Vol 2011 ◽  
pp. 1-8 ◽  
Author(s):  
V. V. Nietz
Keyword(s):  
Magnetic Field ◽  
Phase Transition ◽  
Uniaxial Anisotropy ◽  
Precession Frequency ◽  
Initial Condition ◽  
Configuration Energy ◽  
Wide Range ◽  
Kinetics Of ◽  
New Phase ◽  
The Magnetic Field

The fundamentals of precessing ball solitons (PBS), arising as a result of the energy fluctuations during spin-flop phase transition induced by a magnetic field in antiferromagnets with uniaxial anisotropy, are presented. The PBS conditions exist within a wide range of amplitudes and energies, including negative energies relative to an initial condition. For each value of the magnetic field, there exists a precession frequency for which a curve of PBS energy passes through a zero value (in bifurcation point), and hence, in the vicinity of this point the PBS originate with the highest probability. The characteristics of PBS, including the time dependences of configuration, energy, and precession frequency, are considered. As a result of dissipation, the PBS transform into the macroscopic domains of a new phase.

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