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

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 $k_{\mathrm{B}}{T}_c$, 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.

8 pages, 11 Figures; corrected the wrong sign in Eq. 3

References in corpus (4)

• Local Structure of La1-xSrxCoO3 determined from EXAFS and neutron PDF studies
• Dimensionality Control of d-orbital Occupation in Oxide Superlattices
• Theoretical Description of Pseudocubic Manganites
• Temperature evolution of superparamagnetic clusters in single-crystal La0.85Sr0.15CoO3 from nonlinear magnetic ac response and neutron depolarization

Cited by in corpus (2)

• Photo-induced insulator-to-metal transition and coherent acoustic phonon propagation in LaCoO${}_3$ thin films explored by femtosecond pump-probe ellipsometry
• Optical signatures of strain-induced ferromagnetism in LaCoO${}_3$ thin film