Ac susceptibility at 140 Hz, coercivity at 0.3 Hz, dc magnetization and Mössbauer spectroscopy on
77Fe were measured in the temperature range between 4.2 and 300 K for amorphous (Fe
1-xMn
x)
77Si
10B
13(

) 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
gobtained from χ
ac-T data for reentrant spin-glass (

) and coincides with T
gfor classical spin-glass (

). The experimental results are discussed by an inhomogeneity model.