Magnetic properties of the mixed spin-5/2 and spin-3/2 Blume-Capel Ising system on the two-fold Cayley tree

• Autorzy: Rachidi Yessoufou , Saliou Amoussa , Felix Hontinfinde
• Języki publikacji: EN

Abstrakty

EN

We use exact recursion relations to study the magnetic properties of the half-integer mixed spin-5/2 and spin-3/2 Blume-Capel Ising ferromagnetic system on the two-fold Cayley tree that consists of two sublattices A and B. Two positive crystal-field interactions Δ1 and Δ2 are considered for the sublattice with spin-5/2 and spin-3/2 respectively. For different coordination numbers q of the Cayley tree sites, the phase diagrams of the model are presented with a special emphasis on the case q = 3, since other values of q reproduce similar results. First, the T = 0 phase diagram is illustrated in the (D A = Δ1/J,D B = Δ2/J) plane of reduced crystal-field interactions. This diagram shows triple points and coexistence lines between thermodynamically stable phases. Secondly, the thermal variation of the magnetization belonging to each sublattice for some coordination numbers q are investigated as well as the Helmoltz free energy of the system. First-order and second-order phase transitions are found. The second-order phase transitions become sharper and sharper when D A or D B increases. The first-order transitions only exist for some appropriate non-zero values of D A and/or D B. The corresponding transition lines never connect to the second-order transition lines. Thus, the non-existence of tricritical points remains one of the key features of the present model. The magnetic exponent β 0 of the model is estimated and found to be ¼ at small values of D A = D B = D and β 0 = ½ at large values of D. At intermediate values of D, there is a crossover region where the magnetic exponent displays interesting behaviours.

Słowa kluczowe

EN

mixed spin model; two-fold cayley tree; recursion relations; magnetization; phase transition

• Czasopismo: Open Physics
• Rocznik: 2009
• Tom: 7
• Numer: 3
• Strony: 555-567

Daty

wydano

2009-09-01

online

2009-06-25

Twórcy

autor

Rachidi Yessoufou

• Département de Physique (FAST) et Institut de Mathématiques et de Sciences Physiques (IMSP), Université d’Abomey-Calavi, 01 BP 613, Porto-Novo, Bénin

autor

Saliou Amoussa

• Département de Physique (FAST) et Institut de Mathématiques et de Sciences Physiques (IMSP), Université d’Abomey-Calavi, 01 BP 613, Porto-Novo, Bénin

autor

Felix Hontinfinde

• Département de Physique (FAST) et Institut de Mathématiques et de Sciences Physiques (IMSP), Université d’Abomey-Calavi, 01 BP 613, Porto-Novo, Bénin,

Bibliografia

• [1] O. Khan, Molecular Magnetism (VCH, New-York, 1993)
• [2] M. Monsuripur, J. Appl. Phys. 61, 1580 (1987) http://dx.doi.org/10.1063/1.338094[Crossref]
• [3] C. Ekiz, M. Keskin, Physica A 317, 517 (2003) http://dx.doi.org/10.1016/S0378-4371(02)01356-0[Crossref]
• [4] C. Ekiz, Physica A 347, 353 (2005) http://dx.doi.org/10.1016/j.physa.2004.08.079[Crossref]
• [5] A. Dakhama, N. Benayad, J. Magn. Magn. Mater. 213, 213 (2000) http://dx.doi.org/10.1016/S0304-8853(99)00606-X[Crossref]
• [6] A. Dakhama, Physica A 252, 225 (2003) http://dx.doi.org/10.1016/S0378-4371(97)00583-9[Crossref]
• [7] P. F. Li, Y. G. Chen, H. Chen, Eur. Phys. J. B 51, 473 (2006) http://dx.doi.org/10.1140/epjb/e2006-00255-1[Crossref]
• [8] T. Kaneyoshi, J. Phys. Soc. Jpn. 56, 2675 (1987) http://dx.doi.org/10.1143/JPSJ.56.2675[Crossref]
• [9] T. Kaneyoshi, Physica A 303, 507 (2002) http://dx.doi.org/10.1016/S0378-4371(01)00491-5[Crossref]
• [10] G. M. Zhang, C. Z. Yang, Phys. Rev. B48, 9452 (1993)
• [11] T. W- Tucher, J. Magn. Magn. Mater. 195, 733 (1999) http://dx.doi.org/10.1016/S0304-8853(99)00302-9[Crossref]
• [12] B. Boechat, R. A. Filgueiras, C. Cordeiro, N. S. Branco, Physica A 304, 429 (2002) http://dx.doi.org/10.1016/S0378-4371(01)00560-X[Crossref]
• [13] X. Zhang, X.-M. Kong, Physica A 369, 589 (2006) http://dx.doi.org/10.1016/j.physa.2006.02.014[Crossref]
• [14] C. F. Delale, Int. J. Mod. Phys. B 3, 1523 (1989) http://dx.doi.org/10.1142/S0217979289000981[Crossref]
• [15] E. Albayrak, M. Keskin, Eur. Phys. J. B 24, 505 (2001) http://dx.doi.org/10.1007/s10051-001-8704-3[Crossref]
• [16] C. Ekiz, J. Magn. Magn. Mater. 293, 759 (2005) http://dx.doi.org/10.1016/j.jmmm.2004.11.532[Crossref]
• [17] Q. Zhang, G. Wei, W. Gu, Phys. Status Solidi B 242, 924 (2005) http://dx.doi.org/10.1002/pssb.200402104[Crossref]
• [18] E. Albayrak, A. Yigit, Phys. Lett. A, 353, 121 (2006) http://dx.doi.org/10.1016/j.physleta.2005.12.077[Crossref]

Identyfikatory

DOI

10.2478/s11534-009-0016-x