Quantum Critiality and Collective Effects in Low Dimensional Magnet   CuGeO3 Probed by High Frequency EPR
  For the CuGeO3 single crystals 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). The description of the temperature dependences of the line width and g-factor could be obtained in the OA theory assuming that staggered component of the magnetic moment is located predominantly along b axis. Possible arguments favoring the competition between effects of the staggered field and antiferromagnetic ordering are provided. 
S.V Demishev, A.V.Semeno, A.A.Pronin, N.E.Sluchanko, N.A.Samarin,   H.Ohta, S.Okubo, M.Kimata, K.Koyama, M. Motokawa, A.V.Ku...