中国物理B ›› 2012, Vol. 21 ›› Issue (2): 20511-020511.doi: 10.1088/1674-1056/21/2/020511

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Ali Yigit1,Erhan Albayrak 2   

  • 收稿日期:2011-04-11 修回日期:2011-11-03 出版日期:2012-01-30 发布日期:2012-01-30
  • 通讯作者: Erhan Albayrak,albayrak@erciyes.edu.tr E-mail:albayrak@erciyes.edu.tr

Critical properties of mixed spin-1 and spin-5/2 with equal and unequal crystal fields

Ali Yigita) and Erhan Albayrakb)†   

  1. a. Çankhirhi Karatekin University, Department of Physics, 18100, Çankhirhi, Turkey;
    b. Erciyes University, Department of Physics, 38039, Kayseri, Turkey
  • Received:2011-04-11 Revised:2011-11-03 Online:2012-01-30 Published:2012-01-30
  • Contact: Erhan Albayrak,albayrak@erciyes.edu.tr E-mail:albayrak@erciyes.edu.tr
  • Supported by:
    Project supported by Scientific Research Found of Karatekin University (Grant No. 2011/10).

Abstract: The effects of assuming equal or unequal crystal fields (CF) on the phase diagrams of a mixed spin-1 and spin-5/2 system are investigated in terms of the recursion relations on the Bethe lattice (BL). The equal CF case was considered for the coordination numbers q=3, 4, and 6, while for q=3 the unequal CF case was also studied. It was found that for the equal CF case, the model exhibits second-order phase transitions and two compensation temperatures for all q, the reentrant behavior for q=4 and first-order phase transitions and tricritical point (TCP) for q=6. In the unequal CF case for q=3, the system yields first- and second-order phase transitions, TCP's, and three compensation temperatures. In addition, the TCP's in a very short range are classified as the stable and unstable ones depending on their free energies.

Key words: mixed spin, Bethe lattice, compensation, ferrimagnet

中图分类号:  (Lattice theory and statistics)

  • 05.50.+q
05.70.Fh (Phase transitions: general studies) 64.60.Cn (Order-disorder transformations) 75.10.Hk (Classical spin models)