Ferromagnetic phase transition in ultra‐thin films

Abstract

The ferromagnetic phase transition in ultra thin films is studied by the many body Green's function method based upon the Heisenberg model with the different surface exchange couplings with respect to bulk one plus a surface second order uniaxial anisotropy. The critical temperature of the system is studied as a function of the ratio S S J J ∆ = / of the surface exchange couplings to the bulk ones and as a function of the surface single ion anisotropic strength K (cross over points). If, the critical temperature of the thin film is larger than the bulk one. We analyse various possible configurations for the surface exchange couplings S J and the surface single ion anisotropic strength

Many-body Green's function theory of Heisenberg films

“…[40], where the competition of the exchange anisotropy with the single-ion anisotropy is investigated for a ferromagnetic S = 1 Heisenberg monolayer, and Ref. [41], where the formalism is applied to multilayers and higher spin values with parameters that are different at the surface and the interior of the film. In Ref.…”

“…Heisenberg monolayer, and Ref. [41], where the formalism is applied to multilayers and higher spin values with parameters that are different at the surface and the interior of the film. In Ref.…”

Monte Carlo simulations of dynamic phase transitions in ferromagnetic thin-films

“…surface atoms are embedded in an environment of lower symmetry than that of the inner atoms and consequently the exchange constants between atoms in the surface region may differ from the bulk value). The surface enhancement phenomenon in finite magnetic materials has attracted considerable amount of interest for both experimentalists [1][2][3][4][5][6] and theorists [7][8][9][10][11][12][13][14][15][16].…”