The magnetization process in the 2-dimensional J ₁ -J ₂ model

Abstract:

We study the α = J ₂ / J ₁ -dependence of the magnetization process in the J₁-J₂ model on a square lattice with frustrating couplings J₂ along the diagonals. Perturbation expansions around α = J ₂ / J ₁ = 0 and α ^-1 = 0 yield an adequate description of the magnetization curve in the antiferromagnetic and collinear antiferromagnetic phase, respectively. The transition from one phase to the other ( 0.5 < α < 0.7) leaves pronounced structures in the longitudinal and transverse structure factors at = (π,π) and = (0,π).