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arXiv · 1207.0095

Anticollinear magnetic order induced by impurities in the frustrated Heisenberg model of pnictides

Cédric Weber·Frédéric Mila
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Abstract

We present Monte Carlo simulations for a classical antiferromagnetic Heisenberg model with both nearest ($J_1$) and next-nearest ($J_2$) exchange couplings on the square lattice in the presence of non-magnetic impurities. We show that the order-by-disorder entropy selection, associated with the Ising-like phase transition that appears for $J_2/J_1>1/2$ in the pure spin model, is quenched at low temperature due to the presence of non-magnetic impurities. Evidences that a new competing order is stabilized around the impurities, and in turn induces a re-entrance phase transition are reported. Implications for local magnetic measurement of the parent compound of iron pnictides are briefly discussed.

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Cédric Weber, Frédéric Mila. 2012-06-30. Anticollinear magnetic order induced by impurities in the frustrated Heisenberg model of pnictides. https://doi.org/10.1103/physrevb.86.184432

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