Magnetic phase transition in antiferromagnetic films

The susceptibility of body-centered cubic lattice (bcc) antiferromagnetic spin-12 through two model: Ising and XY films consisting of n=2,3,4,5n=2,3,4,5, and 6 interacting layers is studied by high-temperature series expansions. Sixth order series in x=βJx=βJ(β=1kBT) have been obtained for free-surface boundary conditions. The high temperature series expansion of the magnetic susceptibility series has been investigated by using the Padé approximant method. The Néel temperatures TN(n)TN(n) as a function of the number of n spin layers in the films is obtained. The critical exponent γ   associated with the magnetic susceptibility is deduced for Ising and XY models. The shifts of the critical temperatures from the bulk value [TN(∞)TN(n)−1] can be described by a power law n−λn−λ with λ=1ν, where ν is the correlation length exponent.