Evidence of Griffiths Phase Behavior in Paramagnetic State of Heavy Fermion Compounds CexLa1-xB6 (0.01≤x≤1)
A. Bogacha, b, A. Azarevicha, c, S. Demisheva, b, V. Glushkova, c, A. Samarina, c, N. Shitsevalovad, V. Filipovd, S. Gabánie, K. Flachbarte, N. Sluchankoa, c
aProkhorov General Physics Institute, RAS, Vavilov str. 38, 119991 Moscow, Russia
bNational University of Science and Technology ``MISIS'', Leninskiy pr.4, Moscow 119049, Russia
cMoscow Institute of Physics and Technology, Moscow Region 141700 Russia
dInstitute for Problems of Materials Science, NASU, Krzhizhanovsky str., 3, 03142 Kyiv, Ukraine
eInstitute of Experimental Physics SAS, Watsonova 47, 04001 Košice, Slovakia
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We have investigated the doping-induced changes of magnetic properties of the archetypal heavy fermion compound CeB6 on a series of substitutional solid solutions CexLa1-xB6 (0.01≤x≤1). For these strongly correlated electron systems high precision measurements of magnetic susceptibility χ(T) were undertaken in small external magnetic field aligned along [100], [110], and [111] directions in the simple cubic lattice of these hexaborides. It was shown that for all crystals and all magnetic field orientations the χ(T) dependences obey a power law χ~T at temperatures between 10 and 200 K. The observed critical exponents α=0.77-0.93 demonstrate a monotonous decrease with the increase of Ce content. It is concluded that such a kind of Griffiths phase-type behavior that differs considerably from the convenient Curie-like dependence should be attributed to the emergence of disordered nanometer-size magnetic clusters of Ce-ions in the RB6 matrix.

DOI:10.12693/APhysPolA.137.782
topics: nanometer magnetic clusters, Griffiths phase