1. Evidence for a Ru$^{4+}$ Kondo Lattice in LaCu$_3$Ru$_4$O$_{12}$
- Author
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Riegg, Stefan, Widmann, Sebastian, Meir, Betina, Sterz, Sebastian, Guenther, Axel, Buettgen, Norbert, Ebbinghaus, Stefan G., Reller, Armin, von Nidda, Hans-Albrecht Krug, and Loidl, A.
- Subjects
Condensed Matter - Strongly Correlated Electrons - Abstract
Rare $d$-electron derived heavy-fermion properties of the solid-solution series LaCu$_3$Ru$_x$Ti$_{4-x}$O$_{12}$ were studied for $1 \leq x \leq 4$ by resistivity, susceptibility, specific-heat measurements, and magnetic-resonance techniques. The pure ruthenate ($x = 4$) is a heavy-fermion metal characterized by a resistivity proportional to $T^2$ at low temperatures $T$. The coherent Kondo lattice formed by the localized Ru 4$d$ electrons is screened by the conduction electrons leading to strongly enhanced effective electron masses. By increasing titanium substitution the Kondo lattice becomes diluted resulting in single-ion Kondo properties like in the paradigm $4f$-based heavy-fermion compound Ce$_x$La$_{1-x}$Cu$_{2.05}$Si$_2$ [M. Ocko {\em et al.}, Phys. Rev. B \textbf{64}, 195106 (2001)]. In LaCu$_3$Ru$_x$Ti$_{4-x}$O$_{12}$ the heavy-fermion behavior finally breaks down on crossing the metal-to-insulator transition close to $x = 2$., Comment: 9 pages, 8 figures
- Published
- 2016
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