Field-induced uniaxial and biaxial nematic phases in the Maier–Saupe–Zwanzig (MSZ) lattice model

Petri, Alberto; Salinas, S. R.

doi:10.1080/02678292.2017.1404151

Cited by 7 publications

(7 citation statements)

References 28 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The existence of a tricritical point on the line of biaxial to paranematic phase transitions is compatible with the predictions of [16], which assumes a more restrictive pair interaction independent of a biaxiality parameter, as well as with those of [6], in which nematogens are intrinsically uniaxial. In the latter case, the located tricritical point is observed for χ < 0 and at the value of the magnetic field necessary for our tricritical point to reach the uniaxial limit ∆ = 0; see the inset in Figure 2b.…”

Section: Phase Diagrams In a Fieldsupporting

confidence: 79%

“…Similarly, the critical field associated with a critical end point of the first-order transition line between the uniaxial and the paranematic phases, which has been observed for a fixed biaxiality parameter by various authors [6,11,12,15,31], corresponds to the value of the field, which makes our simple critical point reach the uniaxial limit ∆ = 0 for χ > 0; see the inset in Figure 2a. Again, the same qualitative behavior for the appearance of a critical end point in the uniaxial-paranematic transition was predicted for hard rods or hard plates with χ > 0 [32].…”

Section: Phase Diagrams In a Fieldsupporting

confidence: 71%

See 1 more Smart Citation

Magnetic Field and Dilution Effects on the Phase Diagrams of Simple Statistical Models for Nematic Biaxial Systems

Rodrigues¹,

Vieira²,

Salinas³

2020

Crystals

View full text Add to dashboard Cite

We use a simple statistical model to investigate the effects of an applied magnetic field and of the dilution of site elements on the phase diagrams of biaxial nematic systems, with an emphasis on the stability of the Landau multicritical point. The statistical lattice model consists of intrinsically biaxial nematogenic units, which interact via a Maier–Saupe potential, and which are characterized by a discrete choice of orientations of the microscopic nematic directors. According to previous calculations at zero field and in the absence of dilution, we regain the well-known sequence of biaxial, uniaxial, and disordered structures as the temperature is increased, and locate the Landau point. We then focus on the topological changes induced in the phase diagram by the application of an external magnetic field, and show that the Landau point is destabilized by the presence of an applied field. On the other hand, in the absence of a field, we show that only a quite strong dilution of nematic sites is capable of destabilizing the Landau point.

show abstract

Section: Phase Diagrams In a Fieldsupporting

confidence: 79%

Section: Phase Diagrams In a Fieldsupporting

confidence: 71%

Magnetic Field and Dilution Effects on the Phase Diagrams of Simple Statistical Models for Nematic Biaxial Systems

Rodrigues¹,

Vieira²,

Salinas³

2020

Crystals

View full text Add to dashboard Cite

show abstract

“…). The uniaxial nematic to biaxial nematic (N U −N B ) phase transition in the presence of an external field also studied theoretically [26,43,44].…”

Section: Introductionmentioning

confidence: 99%

Mean-field theory of isotropic-uniaxial nematic-biaxial nematic phase transitions in an external field

Mukherjee

Mandal³

2019

Phys. Scr.

View full text Add to dashboard Cite

We present a simple mean-field theory to study the effects of an external magnetic field on biaxial nematic liquid crystals. Isotropic-uniaxial nematic-biaxial nematic phase sequence in an external magnetic field is described. We determine the temperature-field phase diagrams. The model predicts two new phase diagrams. It is shown that in the presence of the magnetic field, the first order uniaxial nematic to biaxial nematic and isotropic to uniaxial nematic phase transitions become second order transition at a tricritical point.

show abstract

“…The intersection of the critical line (E 1 = 1, green) with the limit of stability of the biaxial solution (E 2 = 0; blue, dot-dashed) defines a tricritical point. A number of calculations [23][24][25], including our own work for the Maier-Saupe-Zwanzig lattice model [16], indicate that the qualitative features of the stress-temperature phase diagram, for sufficiently small values of the coupling ω, are also present in the field-temperature phase diagram of a uniaxial nematic system.…”

Section: B Biaxial Transitionsmentioning

confidence: 99%

“…Positive values of this susceptibility (χ a > 0) correspond to positive tensions (extension) in the elastic model. In the phase diagrams, either in terms of stress or in terms of fields and temperature, there is a line of first-order transitions that ends at a simple critical point [16]. Negative values of the susceptibility (χ a < 0) lead to a field-induced biaxial phase.…”

Section: Introductionmentioning

confidence: 99%

Uniaxial and biaxial structures in the elastic Maier-Saupe model

2018

Self Cite

View full text Add to dashboard Cite

We perform statistical mechanics calculations to analyze the global phase diagram of a fully connected version of a Maier-Saupe-Zwanzig lattice model with the inclusion of couplings to an elastic strain field. We point out the presence of uniaxial and biaxial nematic structures, depending on temperature T and on the applied stress σ. Under uniaxial extensive tension, applied stress favors uniaxial orientation, and we obtain a first-order boundary along which there is a coexistence of two uniaxial paranematic phases, and which ends at a simple critical point. Under uniaxial compressive tension, stress favors biaxial orientation; for small values of the coupling parameters, the first-order boundary ends at a tricritical point, beyond which there is a continuous transition between a paranematic and a biaxially ordered structure. For some representative choices of the model parameters, we obtain a number of analytic results, including the location of critical and tricritical points and the line of stability of the biaxial phase.

show abstract

Field-induced uniaxial and biaxial nematic phases in the Maier–Saupe–Zwanzig (MSZ) lattice model

Cited by 7 publications

References 28 publications

Magnetic Field and Dilution Effects on the Phase Diagrams of Simple Statistical Models for Nematic Biaxial Systems

Magnetic Field and Dilution Effects on the Phase Diagrams of Simple Statistical Models for Nematic Biaxial Systems

Mean-field theory of isotropic-uniaxial nematic-biaxial nematic phase transitions in an external field

Uniaxial and biaxial structures in the elastic Maier-Saupe model

Contact Info

Product

Resources

About