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arXiv · 1105.0732

Interplay between the Kondo effect and randomness: Griffiths phase in MxTiSe2 (M = Co, Ni, and Fe) single crystals

Minoru Sasaki·Akimasa Ohnishi·Takemasa Kikuchi·Mamoru Kitaura·Ki-Seok Kim·Heon-Jung Kim
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Abstract

We investigate the interplay between the Kondo effect and randomness in MxTiSe2 (M = Co, Ni, and Fe) single crystals. Although the typical low-T upturn of resistivity implies the Kondo effect around the single-ion Kondo temperature \overline{T}_{K}, positive magnetoresistance linearly proportional to the magnetic field and the power-law scaling of magnetization suggest the forbidden coexistence between Kondo effect and time reversal symmetry breaking. This puzzling result is resolved by the Griffiths scenario - disorder-induced distribution of the Kondo temperature produces an effective Kondo temperature (\overline{T}_{K}) much lower than \overline{T}_{K}, allowing unscreened local moments above \overline{T}_{K} and resulting in non-Fermi liquid properties in MxTiSe2 below the percolation threshold (x<xc).

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Minoru Sasaki, Akimasa Ohnishi, Takemasa Kikuchi, Mamoru Kitaura, Ki-Seok Kim, Heon-Jung Kim. 2011-05-04. Interplay between the Kondo effect and randomness: Griffiths phase in MxTiSe2 (M = Co, Ni, and Fe) single crystals. https://doi.org/10.1103/physrevb.82.224416

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