Phase Diagram Effects of a Diluted Surface on a Disordered Ising Film

Mouna Bengrine ； Abdelilah Benyoussef ； Hamid Ez-Zahraouy ； Fouad Mhirech

《Chinese Journal of Physics》 38卷1期 (2000/02) Pp. 64-73

並列摘要

The effects of an amorphized film and a diluted surface on the phase diagrams and magnetic properties of a spin-1/2 Ising film are investigated within a finite cluster approximation. Depending on the value of the concentration p of the dilution couplings at the surface, we found that there exists a critical value pc; when the thickness of the film is increased the critical temperature Tc decreases for p greater than pc, while it increases for p less than pc. Moreover, the critical concentration depends on the amorphizationδ. Indeed, pc increases with increasingδ. Also, the phase diagram represented in (Tc, α), where α represents the strength of the strong coupling at the surface, shows that there exists a critical value of the amorphization δc =δc(p) for p ≠ 1; forδ≤δc(p) long range order occurs for any value of α at low temperature, while for δ＞δc(p) an order-disorder transition occurs at T = 0 andα=αc(δ). The magnetization is calculated as a function of the amorphization δ, the concentration p and the strength α of the strong coupling.