Magnetic phase transition in antiferromagnetic films

The susceptibility of body-centered cubic lattice (bcc) antiferromagnetic spin-1/2 through two model: Ising and XY films consisting of n=2,3,4,5, and 6 interacting layers is studied by high-temperature series expansions. Sixth order series in x=βJ(β=1/(kBT) ) have been obtained for free-surface boundary conditions. The high temperature series expansion of the magnetic susceptibility series has been investigated by using the Pade approximant method. The Neel temperatures 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-λ with λ=1/(ν), where ν is the correlation length exponent.