Thermodynamic properties of the Heisenberg ferromagnetic chain are investigated using the Handscomb quantum Monte-Carlo method. The spin–spin interaction is long-range with the spin coupling parameter depending as r−p on the distance r between spins. Parameter p is in the range 1p⩽4. The...

Within the framework of the effective field theory, we examine the phase transitions of the spin-12 Ising film in a transverse field. We study the critical temperature of the film as a function of the exchange interactions, the transverse field and the film thickness. We find that, if the ratio...

The phase transitions of a ferromagnet spin-1/2 Ising superlattice consisting of two different materials are examined using the effective field theory. The critical temperature of the system is studied as a function of the thickness of the constituents in a unit cell, exchange interactions in...

The phase transitions of a diluted spin-12 Ising film are examined using the framework of the effective field theory with a probability distribution technique that accounts for the single-site spin correlations. The critical temperature Tc/J of the system is calculated as a function of the...