中国物理B ›› 2012, Vol. 21 ›› Issue (6): 67501-067501.doi: 10.1088/1674-1056/21/6/067501

• CONDENSED MATTER: ELECTRONIC STRUCTURE, ELECTRICAL, MAGNETIC, AND OPTICAL PROPERTIES • 上一篇    下一篇

The mixed-spins 1/2 and 3/2 Blume–Capel model with a random crystal field

Erhan Albayrak   

  1. Erciyes University, Department of Physics, 38039, Kayseri, Turkey
  • 收稿日期:2011-08-25 修回日期:2012-01-12 出版日期:2012-05-01 发布日期:2012-05-01

The mixed-spins 1/2 and 3/2 Blume–Capel model with a random crystal field

Erhan Albayrak†   

  1. Erciyes University, Department of Physics, 38039, Kayseri, Turkey
  • Received:2011-08-25 Revised:2012-01-12 Online:2012-05-01 Published:2012-05-01
  • Contact: Erhan Albayrak E-mail:albayrak@erciyes.edu.tr

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摘要： The random crystal field (RCF) effects are investigated on the phase diagrams of the mixed-spins 1/2 and 3/2 Blume-Capel (BC) model on the Bethe lattice. The bimodal random crystal field is assumed and the recursion relations are employed for the solution of the model. The system gives only the second-order phase transitions for all values of the crystal fields in the non-random bimodal distribution for given probability. The randomness does not change the order of the phase transitions for higher crystal field values, i.e., it is always second-order, but it may introduce first-order phase transitions at lower negative crystal field values for the probability in the range about 0.20 and 0.45, which is only the second-order for the non-random case in this range. Thus our work claims that randomness may be used to induce first-order phase transitions at lower negative crystal field values at lower probabilities.

关键词: randomness, crystal field, Bethe lattice, mixed spin, bimodal

Abstract: The random crystal field (RCF) effects are investigated on the phase diagrams of the mixed-spins 1/2 and 3/2 Blume-Capel (BC) model on the Bethe lattice. The bimodal random crystal field is assumed and the recursion relations are employed for the solution of the model. The system gives only the second-order phase transitions for all values of the crystal fields in the non-random bimodal distribution for given probability. The randomness does not change the order of the phase transitions for higher crystal field values, i.e., it is always second-order, but it may introduce first-order phase transitions at lower negative crystal field values for the probability in the range about 0.20 and 0.45, which is only the second-order for the non-random case in this range. Thus our work claims that randomness may be used to induce first-order phase transitions at lower negative crystal field values at lower probabilities.

Key words: randomness, crystal field, Bethe lattice, mixed spin, bimodal

中图分类号:  (Classical spin models)

  • 75.10.Hk
75.30.Kz (Magnetic phase boundaries (including classical and quantum magnetic transitions, metamagnetism, etc.)) 75.50.Gg (Ferrimagnetics)