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arXiv · 1801.02424

Direct observation of double exchange in ferromagnetic La$_{0.7}$Sr$_{0.3}$CoO$_3$ by broadband ellipsometry

P. Friš·D. Munzar·O. Caha·A. Dubroka
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Abstract

We present results of our broadband ellipsometry measurements of the optical response of ferromagnetic La$_{0.7}$Sr$_{0.3}$CoO$_3$. Our data show that the ferromagnetic transition is accompanied by a transfer of optical spectral weight from an absorption band centered at 1.5 eV to a narrow component of the Drude-like peak. The associated reduction of the intraband kinetic energy is significantly larger than $k_{\rm B}T_c$, confirming that the double exchange plays a major role in the ferromagnetism of doped cobaltites. In conjunction with results of recent theoretical studies, the temperature dependence of the Drude-like peak suggests that the double exchange is mediated by $t_{2g}$ orbitals.

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P. Friš, D. Munzar, O. Caha, A. Dubroka. 2018-02-14. Direct observation of double exchange in ferromagnetic La$_{0.7}$Sr$_{0.3}$CoO$_3$ by broadband ellipsometry. https://doi.org/10.1103/physrevb.97.045137

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