Intrinsic volume scaling of thermoinduced magnetization in antiferromagnetic nanoparticles

Thermoinduced magnetization (TiM) is a ferromagnetic response recently predicted to occur in nanoparticles of normally antiferromagnetic material. This Rapid Communication presents Monte Carlo estimates for the magnetization and susceptibility which indicate that TiM is an intrinsic property of the antiferromagnetic Heisenberg model below the Néel temperature. The dependence of TiM on the volume is found to be a function of both temperature and anisotropy, in contrast to the original theory for which the volume dependence is independent of temperature and anisotropy. The volume dependence suggests that TiM is related to the divergence of the susceptibility at zero wave vector for three-dimensional systems with continuous order-parameter symmetry.