Second-Virial Onsager Theory and Its Limitations in the Prediction of the Ordering Transitions of Confined Hard Rods between Two Parallel Hard Walls

2020 ◽  
Vol 89 (11) ◽  
pp. 114601
Author(s):  
Seyed Mohammad Ghazi ◽  
Fahimeh Behzadi ◽  
Roohollah Aliabadi
Author(s):  
K. Slyusarenko ◽  
V. Reshetnyak ◽  
Yu. Reznikov

The Onsager theory of hard rod dispersion in a neutral solvent is extended to a case of two-component dispersion consisting of both non-magnetic and magnetic rods. It was found that the alignment of magneto-sensitive dispersion component by a magnetic field leads to the alignment of non-magnetic component in the dispersion and to an elimination of the isotropic phase. This effect is significant even at low relative concentrations of magnetic rods and leads to a magnetically induced anisotropy in a non-magnetic dispersion of rods mixed with the magnetic ones.


2018 ◽  
Vol 97 (1) ◽  
Author(s):  
Roohollah Aliabadi ◽  
Péter Gurin ◽  
Enrique Velasco ◽  
Szabolcs Varga

2021 ◽  
Vol 6 (1) ◽  
Author(s):  
Haibiao Zhou ◽  
Qiyuan Feng ◽  
Yubin Hou ◽  
Masao Nakamura ◽  
Yoshinori Tokura ◽  
...  

AbstractThe CE phase is an extraordinary phase exhibiting the simultaneous spin, charge, and orbital ordering due to strong electron correlation. It is an ideal platform to investigate the role of the multiple orderings in the phase transitions and discover emergent properties. Here, we use a cryogenic high-field magnetic force microscope to image the phase transitions and properties of the CE phase in a Pr0.5Ca0.5MnO3 thin film. In a high magnetic field, we observed a clear suppression of magnetic susceptibility at the charge-ordering insulator transition temperature (TCOI), whereas, at the Néel temperature (TN), no significant change is observed. This observation favors the scenario of strong antiferromagnetic correlation developed below TCOI but raises questions about the Zener polaron paramagnetic phase picture. Besides, we discoverd a phase-separated surface state in the CE phase regime. Ferromagnetic phase domains residing at the surface already exist in zero magnetic field and show ultra-high magnetic anisotropy. Our results provide microscopic insights into the unconventional spin- and charge-ordering transitions and revealed essential attributes of the CE phase, highlighting unusual behaviors when multiple electronic orderings are involved.


Entropy ◽  
2021 ◽  
Vol 23 (7) ◽  
pp. 846
Author(s):  
Donya Ohadi ◽  
David S. Corti ◽  
Mark J. Uline

Modifications to the traditional Onsager theory for modeling isotropic–nematic phase transitions in hard prolate spheroidal systems are presented. Pure component systems are used to identify the need to update the Lee–Parsons resummation term. The Lee–Parsons resummation term uses the Carnahan–Starling equation of state to approximate higher-order virial coefficients beyond the second virial coefficient employed in Onsager’s original theoretical approach. As more exact ways of calculating the excluded volume of two hard prolate spheroids of a given orientation are used, the division of the excluded volume by eight, which is an empirical correction used in the original Lee–Parsons resummation term, must be replaced by six to yield a better match between the theoretical and simulation results. These modifications are also extended to binary mixtures of hard prolate spheroids using the Boublík–Mansoori–Carnahan–Starling–Leland (BMCSL) equation of state.


2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Mikheil Kharbedia ◽  
Niccolò Caselli ◽  
Diego Herráez-Aguilar ◽  
Horacio López-Menéndez ◽  
Eduardo Enciso ◽  
...  

AbstractFaraday waves, or surface waves oscillating at half of the natural frequency when a liquid is vertically vibrated, are archetypes of ordering transitions on liquid surfaces. Although unbounded Faraday waves patterns sustained upon bulk frictional stresses have been reported in highly viscous fluids, the role of surface rigidity has not been investigated so far. Here, we demonstrate that dynamically frozen Faraday waves—that we call 2D-hydrodynamic crystals—do appear as ordered patterns of nonlinear gravity-capillary modes in water surfaces functionalized with soluble (bio)surfactants endowing in-plane shear stiffness. The phase coherence in conjunction with the increased surface rigidity bears the Faraday waves ordering transition, upon which the hydrodynamic crystals were reversibly molded under parametric control of their degree of order, unit cell size and symmetry. The hydrodynamic crystals here discovered could be exploited in touchless strategies of soft matter and biological scaffolding ameliorated under external control of Faraday waves coherence.


Langmuir ◽  
2015 ◽  
Vol 31 (16) ◽  
pp. 4741-4751 ◽  
Author(s):  
Sumyra Sidiq ◽  
Indu Verma ◽  
Santanu Kumar Pal

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