Nonmagnetic impurities in two- and three-dimensional Heisenberg antiferromagnets

In this paper we study in a large-S expansion the effects of substituting spins by nonmagnetic impurities in two- and three-dimensional Heisenberg antiferromagnets in a weak magnetic field. In particular, we demonstrate a mechanism where magnetic moments are induced around nonmagnetic impurities when magnetic field is present. As a result, Curie-type behavior in magnetic susceptibility can be observed well below the Néel temperature, in agreement with what is observed in ${\mathrm{La}}_2$ ${\mathrm{Cu}}_{1\mathrm{-}\mathit{x}}$ ${\mathrm{Zn}}_{\mathit{x}}$ ${\mathrm{O}}_4$ and Sr(${\mathrm{Cu}}_{1\mathrm{-}\mathit{x}}$ ${\mathrm{Zn}}_{\mathit{x}}$ ${)}_2$ ${\mathrm{O}}_3$ compounds. © 1996 The American Physical Society.