97-22U

# 97-22U

By - Posted on 08 February 2012

UDC:
548:537.611.44
PACS:
75.10.H

Investigation of Ising type model with arbitrary value of spin within two-particle cluster approximation. Correlation functions of Blume-Emery-Griffiths model

R.R. Levitskii
O.R. Baran
S.I. Sorokov

The Ising model with an arbitrary value of spin is investigated within the two-particle cluster approximation. For this model on hypercubic lattices the expressions for the pair correlation functions in $\mathaccent "017E\relax {q}$-space are obtained. For the Blume-Emery-Griffiths model in the cases $K'=0$, $D=0$ ($K'$ - biquadratic interaction, $D$ - single-ion anisotropy) and in the case $D=- {\begingroup 8\endgroup \over 3}zK'$ (quadrupolar model) the phase diagrams are constracted and the temperature dependences of thermodinamical characteristics and pair correlation functions at $\mathaccent "017E\relax {q}=0$ are calculated. For this model on a simple cubic lattice a projection of the phase diagram on $(D - K')$ plane is constructed. The temperature dependences of single-site and pair correlation functions at ${\mathaccent "017E\relax q}=0$ are calculated at various values of parameters $D$ and $K'$.

Year:
1997
Pages:
52