| Autor: |
Silva D; Department of Physics, Florida State University, Tallahassee, Florida 32306-4350, USA., Buendía GM; Department of Physics, Universidad Simón Bolívar, Caracas 1080, Venezuela., Rikvold PA; Department of Physics, Florida State University, Tallahassee, Florida 32306-4350, USA.; PoreLab, NJORD Centre, Department of Physics, University of Oslo, P.O. Box 1048 Blindern, 0316 Oslo, Norway. |
| Jazyk: |
angličtina |
| Zdroj: |
Physical review. E [Phys Rev E] 2023 Aug; Vol. 108 (2-1), pp. 024122. |
| DOI: |
10.1103/PhysRevE.108.024122 |
| Abstrakt: |
We present a detailed study by Monte Carlo simulations and finite-size scaling analysis of the phase diagram and ordered bulk phases for the three-dimensional Blume-Capel antiferromagnet in the space of temperature and magnetic and crystal fields (or two chemical potentials in an equivalent lattice-gas model with two particle species and vacancies). The phase diagram consists of surfaces of second- and first-order transitions that enclose a "volume" of ordered phases in the phase space. At relatively high temperatures, these surfaces join smoothly along a line of tricritical points, and at zero magnetic field we obtain good agreement with known values for tricritical exponent ratios [Y. Deng and H. W. J. Blöte, Phys. Rev. E 70, 046111 (2004)10.1103/PhysRevE.70.046111]. In limited field regions at lower temperatures (symmetric under reversal of the magnetic field), the tricritical line for this three-dimensional model bifurcates into lines of critical endpoints and critical points, connected by a surface of weak first-order transitions inside the region of ordered phases. This phenomenon is not seen in the two-dimensional version of the same model. We confirm the location of the bifurcation as previously reported [Y.-L. Wang and J. D. Kimel, J. Appl. Phys. 69, 6176 (1991)0021-897910.1063/1.348797], and we identify the phases separated by this first-order surface as antiferromagnetically (three-dimensional checker-board) ordered with different vacancy densities. We visualize the phases by real-space snapshots and by structure factors in the three-dimensional space of wave vectors. |
| Databáze: |
MEDLINE |
| Externí odkaz: |
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