Magnetic properties of amorphous Mn x Y 100− x alloys have been investigated by means of the measurement of magnetization and low field AC-susceptibility at temperature range from 4.2 K to room temperature. All the samples investigated show spin glass properties at low-temperature region. The spin glass transition temperature T g increases linearly with increasing Mn content. This spin glass characteristic results from the frustration in the spin system which is caused by the competition of positive and negative interactions between the randomly distributed Mn atoms.
