English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

Experiments on the $Gd^{3+}$ Electron Spin Resonance (ESR) in the filledskutterudite $Ce_{1-x}Gd_{x}Fe_{4}P_{12}$ ($x \approx 0.001$), at temperatureswhere the host resistivity manifests a smooth insulator-metal crossover,provides evidence of the underlying Kondo physics associated with this system.At low temperatures (below $T \approx K$), $Ce_{1-x}Gd_{x}Fe_{4}P_{12}$ behavesas a Kondo-insulator with a relatively large hybridization gap, and the$Gd^{3+}$ ESR spectra displays a fine structure with lorentzian line shape,typical of insulating media. The electronic gap is attributed to the largehybridization present in the coherent regime of a Kondo lattice, when Ce4f-electrons cooperate with band properties at half-filling. Mean-fieldcalculations suggest that the electron-phonon interaction is fundamental atexplaining the strong 4f-electron hybridization in this filled skutterudite.The resulting electronic structure is strongly temperature dependent, and atabout $T^{*} \approx 160 K$ the system undergoes an insulator-to-metaltransition induced by the withdrawal of 4f-electrons from the Fermi volume, thesystem becoming metallic and non-magnetic. The $Gd^{3+}$ ESR fine structurecoalesces into a single dysonian resonance, as in metals. Still, oursimulations suggest that exchange-narrowing via the usual Korringa mechanism,alone, is not capable of describing the thermal behavior of the ESR spectra inthe entire temperature region ($4.2$ - $300$ K). We propose that temperatureactivated fluctuating-valence of the Ce ions is the missing ingredient that,added to the usual exchange-narrowing mechanism, fully describes this uniquetemperature dependence of the $Gd^{3+}$ ESR fine structure observed in$Ce_{1-x}Gd_{x}Fe_{4}P_{12}$.

Collapse of the $Gd^{3+}$ ESR fine structure throughout the coherent temperature of the Gd-doped Kondo Semiconductor $CeFe_{4}P_{12}$