text: teractions by including six diﬀerent exchange constants 
  along the c crystallographic axis, and gives a helix pitch 
  wave-vector Qz such that Qzc′ ≃ 30◦, where c′ = c/2 is 
  the distance between nearest neighboring spin layers par- 
  allel to the ab crystallographic planes, henceforth denoted 
  also as x − y planes, while z will be taken parallel to c. 
  For n > 16, n being the number of spin layers in the ﬁlm, 
  a correct bulk limit is reached, while for lower n the ﬁlm 
  properties are clearly aﬀected by the strong competition 
  among the helical pitch and the surface eﬀects, which in- 
  volve the majority of the spin layers. 
  In the thickness 
  range n = 9 − 16, i.e. right for thickness values com- 
  parable with the helical pitch, three diﬀerent magnetic 
  phases emerged, with the high-temperature, disordered, 
  paramagnetic phase and the low-temperature, long-range 
  ordered one separated by an intriguing, 
  intermediate- 
  temperature block phase, where outer ordered layers co- 
  exist with some inner disordered ones, the phase tran- 
  sition of the latter eventually displaying the signatures 
  of a Kosterlitz-Thouless one. Finally, for n ≤ 7 the ﬁlm 
  collapses once and for all to a quasi-collinear order. 