Very low field AC-response at the loss of long range magnetic order in amorphous Fe/sub 90/Zr/sub 10/

Low temperature AC-susceptibility measurements over five decades of AC field (0.08-8000 A/m) are carried out on amorphous ribbons of Fe/sub 90/Zr/sub 10/ and Fe/sub 91/Zr/sub 9/. It is found that at very low fields (0.8 to 24 A/m), AC response measurements eliminate the influence of domain and domain wall motion to reveal clearly the reentrant characteristics. With such studies, a reentrant freezing temperature T/sub sf/ is unambiguously revealed with an evident knee in chi '(T) and a corresponding well defined peak in chi "(T). The latter is found to be independent of the applied field (0.8 to 8 A/m), while being weakly dependent on the frequency (10-1000 Hz). T/sub sf/ is found to be 25 K and 40 K, respectively, for Fe/sub 90/Zr/sub 10/ and Fe/sub 91/Zr/sub 9/ amorphous ribbons.<>