中国物理B ›› 2012, Vol. 21 ›› Issue (11): 110503-110503.doi: 10.1088/1674-1056/21/11/110503

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Phase diagrams of the spin-2 Ising model in the presence of a quenched diluted crystal field distribution

Ali Yigita, Erhan Albayrakb   

  1. a Cankiri Karatekin University, Department of Physics, Cankiri 18100, Turkey;
    b Erciyes University, Department of Physics, Kayseri 38039, Turkey
  • 收稿日期:2012-04-25 出版日期:2012-10-01 发布日期:2012-10-01

Phase diagrams of the spin-2 Ising model in the presence of a quenched diluted crystal field distribution

Ali Yigita, Erhan Albayrakb   

  1. a Cankiri Karatekin University, Department of Physics, Cankiri 18100, Turkey;
    b Erciyes University, Department of Physics, Kayseri 38039, Turkey
  • Received:2012-04-25 Online:2012-10-01 Published:2012-10-01
  • Contact: Ali Yigit E-mail:ayigit80@karatekin.edu.tr

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摘要： We have investigated the random crystal field effects on the phase diagrams of the spin-2 Blume-Capel model for the honeycomb lattice using the effective-field theory with correlations. To do so, the thermal variations of magnetization are studied via calculating the phase diagrams of the model. We have found that the model displays both second-order and first-order phase transitions in addition to the tricritical and isolated points. Reentrant behavior is also observed for some appropriate values of certain system parameters. Besides the usual ground-state phases of spin-2 model including ±2, ±1, and 0, we have also observed the phases ±3/2 and ±1/2 which are unusual for spin-2 case.

关键词: spin-2 model, random crystal field, effective-field theory, isolated critical points and triciritical points

Abstract: We have investigated the random crystal field effects on the phase diagrams of the spin-2 Blume-Capel model for the honeycomb lattice using the effective-field theory with correlations. To do so, the thermal variations of magnetization are studied via calculating the phase diagrams of the model. We have found that the model displays both second-order and first-order phase transitions in addition to the tricritical and isolated points. Reentrant behavior is also observed for some appropriate values of certain system parameters. Besides the usual ground-state phases of spin-2 model including ±2, ±1, and 0, we have also observed the phases ±3/2 and ±1/2 which are unusual for spin-2 case.

Key words: spin-2 model, random crystal field, effective-field theory, isolated critical points and triciritical points

中图分类号:  (Fluctuation phenomena, random processes, noise, and Brownian motion)

  • 05.40.-a
05.50.+q (Lattice theory and statistics) 64.60.De (Statistical mechanics of model systems (Ising model, Potts model, field-theory models, Monte Carlo techniques, etc.))