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Spin Order due to Orbital Fluctuations: Cubic Vanadates

G. Khaliullin·P. Horsch·A. M. Oles
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Abstract

We investigate the highly frustrated spin and orbital superexchange interactions in cubic vanadates. The fluctuations of $t_{2g}$ orbitals trigger a {\it novel mechanism of ferromagnetic interactions} between spins S=1 of V$^{3+}$ ions along one of the cubic directions which operates already in the absence of Hund's rule exchange $J_H$, and leads to the C-type antiferromagnetic phase in LaVO$_3$. The Jahn-Teller effect can stabilize the orbital ordering and the G-type antiferromagnetic phase at low temperatures, but large entropy due to orbital fluctuations favors again the C-phase at higher temperatures, as observed in YVO$_3$.

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G. Khaliullin, P. Horsch, A. M. Oles. 2001-03-14. Spin Order due to Orbital Fluctuations: Cubic Vanadates. https://doi.org/10.1103/physrevlett.86.3879

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