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Why rare-earth ferromagnets are so rare: Insights from the p-wave Kondo model

Ahamed, Shadab and Moessner, Roderich and Erten, Onur (2018) Why rare-earth ferromagnets are so rare: Insights from the p-wave Kondo model. In: PHYSICAL REVIEW B, 98 (5).

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Official URL: http://dx.doi.org/10.1103/PhysRevB.98.054420

Abstract

Magnetic exchange in Kondo lattice systems is of the Ruderman-Kittel-Kasuya-Yosida type, whose sign depends on the Fermi wave vector k(F). In the simplest setting, for small k(F), the interaction is predominately ferromagnetic, whereas it turns more antiferromagnetic with growing k(F). It is remarkable that even though k(F) varies vastly among the rare-earth systems, an overwhelming majority of lanthanide magnets are in fact antiferromagnets. To address this puzzle, we investigate the effects of a p-wave form factor for the Kondo coupling pertinent to nearly all rare-earth intermetallics. We show that this leads to interference effects which for small k(F) are destructive, greatly reducing the size of the RKKY interaction in the cases where ferromagnetism would otherwise be strongest. By contrast, for large k(F), constructive interference can enhance antiferromagnetic exchange. Based on this, we propose a route for designing ferromagnetic rare-earth magnets.

Item Type: Journal Article
Additional Information: Copy right for this article belong to AMER PHYSICAL SOC, ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA
Department/Centre: Division of Physical & Mathematical Sciences > Physics
Depositing User: Id for Latest eprints
Date Deposited: 06 Sep 2018 15:43
Last Modified: 06 Sep 2018 15:43
URI: http://eprints.iisc.ac.in/id/eprint/60582

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