Investigations of even-order harmonic susceptibilities of MgB/sub 2/ superconductors using critical state approach

Even-order harmonic susceptibilities (chi)/sub n/=(chi)/sub n/ʹ+i(chi)/sub n/ʹʹ (n is even) of MgB/sub 2/ were measured at temperatures between 15 and 45 K with small ac and dc field combinations. The simplified Kim model was employed to account for the main features of the experiments by use of a fitting equation H/sub p/=H/sub (alpha)/(1-t)/sup (beta)/ for temperature scaling. The experiments are in qualitative agreement with theory.