Determination of the critical exponent gamma from AC susceptibility measurements on amorphous ferromagnetic alloys

Detailed AC susceptibility measurements have been performed on amorphous Fe x Ni 80-x B 19 Si 1 , x=10, 13, 16, and Fe 91 Zr 9 alloys in the critical region. In accordance with the predictions of the renormalisation group calculations and the Harris criterion, the critical exponent gamma of the pure (ordered) system is found to remain unaffected (within the error limits) in the presence of a quenched disorder which is not too strong.