Magnetization and Mössbauer-effect investigations in amorphous (Fe1-xMnx)77Si10B13alloys

Ac susceptibility at 140 Hz, coercivity at 0.3 Hz, dc magnetization and Mössbauer spectroscopy on
⁷⁷
Fe were measured in the temperature range between 4.2 and 300 K for amorphous (Fe
1-x
Mn
x
)
77
Si
10
B
13
(
0.2 \leq x \leq 0.8
) alloys. The magnetic phase diagram is obtained based on the χ
ac
-T data. A steep increase in average hyperfine field is observed below T. This temperature is lower than the freezing temperature T
g
obtained from χ
ac
-T data for reentrant spin-glass (
0.2 \leq x \leq 0.36
) and coincides with T
g
for classical spin-glass (
x \leq 0.4
). The experimental results are discussed by an inhomogeneity model.