Thickness dependent Curie temperature and power-law behavior of layering   transitions in ferromagnetic classical and quantum thin films described by   Ising, XY and Heisenberg models
  Ferromagnetic-paramagnetic phase transitions in classical and quantum thin films have been studied up to 50 mono-layers using effective field theory with two-site cluster approximation. Variation of the Curie temperature as a function of film thickness has been examined. The relative shift of the Curie temperature from the corresponding bulk value has been investigated in terms of the shift exponent $\lambda$. We have found that shift exponent $\lambda$ clearly depends on the strength of the ferromagnetic exchange coupling of the surface. Moreover, we have not observed any significant difference between classical and quantum exponents for a particular model. 
Yusuf Yuksel, Umit Akinci
cond-mat.stat-mech cond-mat.str-el