scholarly journals Unconventional critical behaviour in weak ferromagnets Fe2-xMnxCrAl (0 ≤ x < 1)

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Kavita Yadav ◽  
Dheeraj Ranaut ◽  
K. Mukherjee
Keyword(s):  
Critical Exponent ◽  
Equations Of State ◽  
Critical Phenomenon ◽  
Scaling Law ◽  
Universality Class ◽  
Critical Behaviour ◽  
Ferromagnetic Transition ◽  
Parent Alloy ◽  
Mn Content ◽  
Mn Concentration

AbstractRecent investigation on weak ferromagnets Fe2-xMnxCrAl (0 ≤ x < 1) reveal the existence of a cluster glass phase (CGP) and a Griffiths-like phase (GP) below and above the ferromagnetic transition temperature (TC), respectively [(2019) Sci. Rep.9 15888]. In this work, the influence of these inhomogeneous phases on the critical behaviour (around TC) of the above-mentioned series of alloys has been investigated in detail. For the parent alloy Fe2CrAl, the critical exponent γ is estimated as ~ 1.34, which lies near to the ordered 3D Heisenberg class, whereas the obtained value of the critical exponent β ~ 0.273 does not belong to any universality class. With increment in Mn concentration, both exponents γ and β increase, where γ and β approach the disordered and ordered 3D Heisenberg class, respectively. The observed deviation of γ and unconventional value of δ can be ascribed to the increment of GP with Mn-concentration. The trend noted for β can be attributed to the increment in CGP regime with an increase in Mn-content. The estimated critical exponents are consistent and reliable as corroborated using the scaling law and equations of state. Our studies indicate that the critical phenomenon of Fe2-xMnxCrAl (0 ≤ x < 1) alloys possibly belong to a separate class, which is not described within the framework of any existing universal model.

scholarly journals Universality class of the motility-induced critical point in large scale off-lattice simulations of active particles.

Soft Matter ◽  
2021 ◽  
Author(s):  
Claudio Maggi ◽  
Matteo Paoluzzi ◽  
Andrea Crisanti ◽  
Emanuela Zaccarelli ◽  
Nicoletta Gnan
Keyword(s):  
Phase Separation ◽  
Critical Point ◽  
Computer Simulations ◽  
Large Scale ◽  
Universality Class ◽  
Critical Behaviour ◽  
Two Dimensional ◽  
Dimensional Model ◽  
Active Particles ◽  
Two Dimensional Model

We perform large-scale computer simulations of an off-lattice two-dimensional model of active particles undergoing a motility-induced phase separation (MIPS) to investigate the systems critical behaviour close to the critical point...

Equilibrium and nonequilibrium models on solomon networks with two square lattices

2017 ◽  
Vol 28 (08) ◽  
pp. 1750099
Author(s):  
F. W. S. Lima
Keyword(s):  
Monte Carlo ◽  
Monte Carlo Simulations ◽  
Critical Exponent ◽  
Critical Points ◽  
Majority Vote ◽  
Universality Class ◽  
2D Systems ◽  
Two Dimensional ◽  
Critical Properties ◽  
Regular Lattices

We investigate the critical properties of the equilibrium and nonequilibrium two-dimensional (2D) systems on Solomon networks with both nearest and random neighbors. The equilibrium and nonequilibrium 2D systems studied here by Monte Carlo simulations are the Ising and Majority-vote 2D models, respectively. We calculate the critical points as well as the critical exponent ratios [Formula: see text], [Formula: see text], and [Formula: see text]. We find that numerically both systems present the same exponents on Solomon networks (2D) and are of different universality class than the regular 2D ferromagnetic model. Our results are in agreement with the Grinstein criterion for models with up and down symmetry on regular lattices.

scholarly journals Critical behaviour of transport coefficients at a structural-ferromagnetic transition

1979 ◽  
Vol 40 (C5) ◽  
pp. C5-42-C5-43 ◽  
Author(s):  
J. B. Sousa ◽  
M. M. Amado ◽  
R. P. Pinto ◽  
J. M. Moreira ◽  
M. E. Braga ◽  
...  
Keyword(s):  
Transport Coefficients ◽  
Critical Behaviour ◽  
Ferromagnetic Transition

Quantitative Determination of Low Contents of Manganese in Steels by EPMA

2019 ◽  
Vol 25 (3) ◽  
pp. 625-629 ◽  
Author(s):  
Daoling Wang ◽  
Aiqin Sun
Keyword(s):  
Calibration Curve ◽  
Alloy Element ◽  
Correction Method ◽  
Time Saving ◽  
Curve Method ◽  
Mn Content ◽  
Alloy Standard ◽  
Mn Concentration ◽  
Probe Measurements

AbstractThe fluorescence effect induced by Kβ photons is usually so small that it can be neglected. However, in the Fe–Mn system, omitting Kβ fluorescence correction will lead to the overestimation of the Mn content especially when Mn is the minor alloy element. In this study, the error in the Mn concentration induced by Kβ fluorescence was investigated by both Monte Carlo simulation, using the pyPENELOPE program, and systematic electron probe measurements on the Fe–0.53% Mn alloy standard by the aid of CalcZAF software. It is shown that the error caused by Kβ fluorescence exceeds 4% for the Fe–0.53% Mn alloy. The problem can be overcome by utilizing CalcZAF in which β-line fluorescence has been included, or by employing a similar standard Fe–0.85% Mn for Mn in the absence of β-line fluorescence correction. In addition, a modified calibration curve method, using k-values instead of X-ray intensity as a variable, is presented and used to measure the Mn concentration. The accuracy of this method is as good as or better than that of the conventional matrix correction method. Compared with conventional calibration curve methods, it is time-saving because the k-value is not sensitive to instrument fluctuations and the established curve remains valid for a long period.

Phase Densities of Molten Binary Mixtures of Alkali Halogenides with Limited Mutual Solubility

2007 ◽  
Vol 62 (5-6) ◽  
pp. 303-308 ◽  
Author(s):  
Vera N. Lockett ◽  
Irina V. Rukavishnikova ◽  
Viktor P. Stepanov
Keyword(s):  
Critical Exponent ◽  
Critical Point ◽  
Binary Mixtures ◽  
Order Parameter ◽  
Mutual Solubility ◽  
Critical Behaviour ◽  
Density Measurements

The densities of binary mixtures of LiF with CsCl, KBr, RbBr, CsBr, KI, RbI and CsI have been investigated at 1093 - 1253 K. For the system LiF with KBr the dependence of the density on the temperature was measured up to the critical point, where the system became single-phased, and the critical behaviour was evaluated. The critical exponent of the order parameter, which was found from the density measurements, is close to 0.5.

PERCOLATION PROPERTIES AND UNIVERSALITY CLASS OF A MULTIFRACTAL RANDOM TILING

2005 ◽  
Vol 16 (02) ◽  
pp. 317-325 ◽  
Author(s):  
M. G. PEREIRA ◽  
G. CORSO ◽  
L. S. LUCENA ◽  
J. E. FREITAS
Keyword(s):  
Critical Phenomenon ◽  
Universality Class ◽  
Scaling Exponent ◽  
Two Dimensional ◽  
Regular Lattice ◽  
Local Anisotropy ◽  
Infinite Cluster ◽  
A Value ◽  
Random Tiling ◽  
Correlated Percolation

We study percolation as a critical phenomenon on a random multifractal support. The scaling exponent β related to the mass of the infinite cluster and the fractal dimension of the percolating cluster df are quantities that have the same value as the ones from the standard two-dimensional regular lattice percolation. The scaling exponent ν related to the correlation length is sensitive to the local anisotropy and assumes a value different from standard percolation. We compare our results with those obtained from the percolation on a deterministic multifractal support. The analysis of ν indicates that the deterministic multifractal is more anisotropic than the random multifractal. We also analyze connections with correlated percolation problems and discuss some possible applications.

SURFACE CRITICAL BEHAVIOUR OF SOME TWO-DIMENSIONAL LATTICE MODELS

1990 ◽  
Vol 04 (09) ◽  
pp. 1437-1464 ◽  
Author(s):  
A.L. STELLA ◽  
C. VANDERZANDE
Keyword(s):  
Potts Model ◽  
Conformal Invariance ◽  
Finite Size ◽  
Lattice Models ◽  
Universality Class ◽  
Two Dimensions ◽  
Point Of View ◽  
Critical Behaviour ◽  
Logarithmic Scaling ◽  
Theta Point

A review is given of recent work on the ordinary surface critical behaviour of systems in two dimensions. Several models of interest in statistical mechanics are considered: Potts model, percolation, Ising clusters, ZN-model, O(n) model and polymers. Numerical results for surface exponents, obtained by suitable finite size scaling extrapolations, are discussed in the light of recent advances based on the conformal invariance approach. Surface exponents are often seen as important tests of conformal invariance predictions. In other cases these exponents provide important information for a location of the problem within the classification schemes offered by the conformal approach, and a determination of its universality class. A relevant example of the first aspect is the study of the q-state Potts model with q near 4, for which an analytical study of logarithmic scaling corrections is needed to achieve a successful test. The latter point of view applies, e.g., to the more controversial cases of polymers at the theta point and critical Ising clusters. Emphasis is put on the importance of an integrated study of both bulk and surface properties. Relevant issues, like the possible existence of analytical expressions for the indices in particular model families, or of general relationships between bulk and surface exponents, are critically discussed. The new problem of critical behaviour at fractal boundaries is also considered for random (RW) and self-avoiding walks (SAW). From the numerical analysis of this problem remarkable universalities of the surface exponents seem to emerge, which, in the case of SAW’s, are still far from being understood.

Sign in / Sign up

Export Citation Format

Share Document