MAGNETIC MEDIUM-RANGE ORDER IN AMORPHOUS TBXSI1-X (X = 0.59, 0.87)

The magnetic medium-range order has been determined by small-angle neutron scattering for two TbxSi1-x amorphous alloys (x = 0.59; 0.87). There is coexistence of small spatial fluctuations of the magnetization over long distances and bigger spatial fluctuations over small distances. We also observe some aggregates which are either magnetic or nonmagnetic. The latter allow us to obtain the magnetization of the amorphous sample. The measurements for field cooled and zero-field cooled samples evidence different magnetic behaviour of the part showing spatial fluctuations and aggregates.