Non-Fermi liquid behaviour in CeCoGe3-xSix alloys

We have investigated magnetic ordering and spin fluctuations in the Kondo l attice alloy system CeCoGe3-xSix at x = 1.1 and 1.5 using muon spin relaxat ion (mu SR) method. Temperature and field dependences of muon spin relaxati on rates show strongly disordered heavy-fermion magnetic ordering in CeCoGe 1.9Si1.1 at 1.2 K. The internal field is determined to be broadly distribut ed around 270 G at one of the two mu(+) sites observed in these alloys. Mag netic ordering was not observed down to 34 mK in CeCoGe1.5Si1.5. The spin-l attice relaxation rate lambda(2) at the other mu(+) site (B) follows Korrin ga behaviour below T-N in CcCoCe(1.9)Si(1.1), where as it scales logarithmi cally below 1.5 K in CeCoCe1.5Si1.5 showing a possible non-Fermi liquid beh aviour. (C) 2000 Elsevier Science B.V. All rights reserved.