Itinerant-Electron Magnet of the Pyrochlore Lattice: Indium-Doped YMn2Zn20

Abstract

We report on a ternary intermetallic compound, "YMn2Zn20", comprising a pyrochlore lattice made of Mn atoms. A series of In-doped single crystals undergo no magnetic long-range order down to 0.4 K, in spite of the fact that the Mn atom carries a local magnetic moment at high temperatures, showing Curie-Weiss magnetism. However, In-rich crystals exhibit spin-glass transitions at approximately 10 K due to a disorder arising from the substitution, while, with decreasing In content, the spin-glass transition temperature is reduced to 1 K. Then, heat capacity divided by temperature approaches a large value of 280 mJ K-2 mol-1, suggesting a significantly large mass enhancement for conduction electrons. This heavy-fermion-like behavior is not induced by the Kondo effect as in ordinary f-electron compounds, but by an alternative mechanism related to the geometrical frustration on the pyrochlore lattice, as in (Y,Sc)Mn2 and LiV2O4, which may allow spin entropy to survive down to low temperatures and to couple with conduction electrons.

5 pages, 4 figures, J. Phys. Soc. Jpn., in press

References in corpus (2)

• YSix closely related YbT${}_2$Zn${}_{20}$ (T = Fe, Co, Ru, Rh, Os, Ir) heavy fermion compounds with large local moment degeneracy
• Variation of the magnetic ordering in GdT${}_2$Zn${}_{20}$ (T= Fe, Ru, Os, Co, Rh and Ir) and its correlation with the electronic structure of isostructural YT${}_2$Zn${}_{20}$

Cited by in corpus (7)

• Crystal Chemistry and Magnetic Properties of Manganese Zinc Alloy "YMn2Zn20" Comprising a Mn Pyrochlore Lattice
• Single crystal growth and physical properties of a new uranium compound URhIn${}_5$
• Quest for the Origin of Heavy Fermion Behavior in $d$-Electron Systems
• Hund flat band in a frustrated spinel oxide
• Structural Trends and Itinerant Magnetism of the New Cage-structured Compound HfMn${}_2$Zn${}_{20}$
• Intrinsic Magnetic Excitations and Heavy-Fermion Formation in the Frustrated Mn Pyrochlore System YMn${}_{2+\delta }$Zn${}_{20-x}{X}_x$ ($X$ = In and Al) Revealed by Nuclear Magnetic Resonance and Nuclear Quadrupole Resonance Measurements
• Emergent magnetism, heavy electrons and pressure-induced reentrant superconductivity in the iron substituted 4d transition-metal sulfides