Mixed spin (1/2,1) transverse Ising nanoparticles

Mixed spin 2D-nanoparticles (circle and square) described by the transverse Ising model are investigated by the use of the finite cluster approximation. The effects of the exchange interactions and the transverse field parameters on the phase diagrams are systematically discussed, in particular, it was shown that the transition temperature is not so sensitive to shell exchange interaction, when the spins S are strongly correlated. A number of interesting phenomena have been found such as reentrant behavior. This latter, which is due to the competition between the exchange interaction and core-transverse field, disappears completely for any no-zero shell transverse field.