Monte Carlo investigation of transition and compensation temperatures of Fe/Tb multilayers

A Monte Carlo investigation of the A thickness (A equivalent to Fe) dependence of the transition and compensation temperatures of a simple cubic Heisenberg A/B bilayer is carried out. Our model, which includes a few mixed planes of the A(1-x)B(x) type that represent the disordered interfaces, basically consists of several coupled magnetic parts with different bulk transition temperatures. Numerical results are compared with the experimental data for amorphous Fe/Tb multilayers. The simulated Fe thickness (t(Fe)) dependence of T-C, which reproduces the decrease of T-C as t(Fe) increases, is consistent with the experimental one. Since our simulations indicate that the magnetic ordering is driven by the disordered interfaces, the decrease of T-C is explained by the fact that the interfaces are more and more decoupled as t(Fe) increases. The experimental thermal behavior of each sublattice magnetization can be reproduced with a Tb-magnetic moment of 6 mu(B) which seems to be reasonable for amorphous layers, whereas a value of 9 mu(B) is too large. Accordingly, a compensation point has been observed for a Fe thickness range that agrees with the experimental one. The simulated and experimental Fe thickness variations of T-comp are in reasonable agreement. (C) 2000 American Institute of Physics. [S0021-8979(00)02601-3].