Two-dimensional mixed spin Ising models with bond dilution and random ±J interactions
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- Benayad, N., Klümper, A., Zittartz, J. et al. Z. Physik B - Condensed Matter (1989) 77: 339. doi:10.1007/BF01313679
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Using the finite cluster approximation we study a mixed spin model (spins Φ=1/2 andS=1) on a square lattice with nearest-neighbour and crystal field interactions. The nearest-neighbour couplingsKijare assumed to be independent random variables with distribution,P(Kij)=pδ(Kij−K)+(1−p)δ(Kij−αK), whereK>0. We investigate the cases α=0 and α=−1 corresponding to bond dilution and to random ±J interactions, respectively. In certain ranges ofp the phase diagrams exhibit tricritical behaviour and reentrance.