Spin-1 Blume-Capel model with random crystal field effects

Albayrak E.

PHYSICA A-STATISTICAL MECHANICS AND ITS APPLICATIONS, vol.392, no.4, pp.552-557, 2013 (SCI-Expanded) identifier identifier

  • Publication Type: Article / Article
  • Volume: 392 Issue: 4
  • Publication Date: 2013
  • Doi Number: 10.1016/j.physa.2012.09.026
  • Journal Name: PHYSICA A-STATISTICAL MECHANICS AND ITS APPLICATIONS
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus
  • Page Numbers: pp.552-557
  • Keywords: Random crystal field, Spin-1 Ising model, Cluster variation method, Blume-Capel model, TRANSVERSE ISING-MODEL, EMERY-GRIFFITHS MODEL, RANDOM LONGITUDINAL-FIELD, PHASE-DIAGRAMS, TRICRITICAL BEHAVIOR, MAGNETIC-PROPERTIES, HE-3-HE-4 MIXTURES, BETHE LATTICE, TRIPLET IONS, SYSTEMS
  • Erciyes University Affiliated: Yes

Abstract

The random-crystal field spin-1 Blume-Capel model is investigated by the lowest approximation of the cluster-variation method which is identical to the mean-field approximation. The crystal field is either turned on randomly with probability p or turned off with q = 1-p in a bimodal distribution. Then the phase diagrams are constructed on the crystal field (Delta)-temperature (kT/J) planes for given values of p and on the (kT/J, p) planes for given Delta by studying the thermal variations of the order parameters. In the latter, we only present the second-order phase transition lines, because of the existence of irregular wiggly phase transitions which are not good enough to construct lines. In addition to these phase transitions, the model also yields tricritical points for all values of p and the reentrant behavior at lower p values. (C) 2012 Elsevier B.V. All rights reserved.