PHASE-DIAGRAMS FOR THE TRIANGULAR ISING LATTICE WITH REENTRANT FERROMAGNETISM

We present the phase diagrams in a 2D spin 1/2 Ising model for the tri angular lattice. Using the finite-cluster approximation and renormaliz ation technique we studied a nearest-neighbour random interactions. Fe rromagnetic exchange interactions J are considered with concentration p and exchange interactions alphaJ (\alpha\ less-than-or-equal-to 1) w ith concentration (1 - p). The phase diagrams were obtained for this m odel. They show re-entrant behaviour in certain ranges of the concentr ation p and different alpha.