Disorder driven quantum critical behavior in CuGeO3 doped with magnetic   impurity
  For the CuGeO3 doped with 1% of Fe the quantum critical behavior in a wide temperature range 1-40 K is reported. The critical exponents for susceptibility along different crystallographic axes are determined: a=0.34 (B//a and B//c) and a=0.31 (B//b). New effect of the frequency dependence of the critical exponent is discussed. 
S.V. Demishev, A.V. Semeno, N.E. Sluchanko, N.A. Samarin, A.A. Pronin,   V.V. Glushkov, H. Ohta, S. Okubo, M. Kimata, K. Koy...