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Magnetic Percolation and the Phase Diagram of the Disordered RKKY model

D. J. Priour Jr.·S. Das Sarma
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Abstract

We consider ferromagnetism in spatially randomly located magnetic moments, as in a diluted magnetic semiconductor, coupled via the carrier-mediated indirect exchange RKKY interaction. We obtain via Monte Carlo the magnetic phase diagram as a function of the impurity moment density $n_{i}$ and the relative carrier concentration $n_{c}/n_{i}$. As evidenced by the diverging correlation length and magnetic susceptibility, the boundary between ferromagnetic (FM) and non-ferromagnetic (NF) phases constitutes a line of zero temperature critical points which can be viewed as a magnetic percolation transition. In the dilute limit, we find that bulk ferromagnetism vanishes for $n_{c}/n_{i}>.1$. We also incorporate the local antiferromagnetic direct superexchange interaction between nearest neighbor impurities, and examine the impact of a damping factor in the RKKY range function.

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D. J. Priour Jr., S. Das Sarma. 2006-06-22. Magnetic Percolation and the Phase Diagram of the Disordered RKKY model. https://doi.org/10.1103/physrevlett.97.127201

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