  We have grown and characterized three samples of Co doped MnSi and studied
their physical properties (magnetization and magnetic susceptibility, heat
capacity and electrical resistance). All three samples show non-Fermi liquid
physical properties. From literature data and current results follow that
impurities (Co and Fe) eliminate the first order phase transition peaks and
spread the fluctuation maxima in such a way that its low temperature part
effectively reaches the zero temperature, where the fluctuations inevitably
become quantum. The behavior of low temperature branches of the heat capacity
of the samples suggests that a gradual transition from classical to quantum
fluctuations can be described by a simple power function of temperature with
the exponent less than one. The $d\rho/dT$ data generally support this
suggestion. The values of the heat capacity exponents immediately lead to the
diverging ratio $C_p/T$ and hence to the diverging effective electron mass. We
found out that at large concentration of the dopant there are no distinct phase
transition points. What we observe is a cloud of the helical fluctuations
spreading over a significant range of concentrations and temperatures, which
become quantum close to 0~K.
