High field susceptibility peak in some NiFeSiB amorphous alloys

Magnetization studies of amorphous Ni80-xFexB12Si8 ribbons with 0 ≤ x ≤ 8.0 were carried out in the temperature range 1.7 to 290 K with an applied magnetic field up to 15 T. The high field susceptibility was determined from the linear part of the magnetization curve as function of magnetic field. Temperature dependence of the corrected high field susceptibility χ-hf''' (observed high field susceptibility minus Pauli spin paramagnetism of electrons) for various Fe concentrations x is drawn. With increasing x, χ-hf''' also increases and the peak becomes sharper. The temperature Tf at which this peak occurs increases linearly with x. The results have been discussed on the base of a f.c.c. phase and spin freezing of alloys