Magnetic coupling in amorphous Co-Er films

Amorphous Co100-XErX thin films have been prepared by rf sputtering and their magnetic properties have been studied. The mean field theory has been used to explain the temperature dependence of the magnetization. High-field magnetization studies performed at 4.2 K in magnetic fields up to 5.5 T on amorphous Co-100-Er-X(X) alloys have revealed, for samples with stoichiometry close to that of a compensated ferrimagnet, a magnetic behavior that is characteristic of a noncollinear magnetic structure of the Er and Co sublattices. From the noncollinear regime the exchange interactions between the Co and Er magnetic sublattices have been accurately evaluated. (C) 1999 American Institute of Physics. [S0021-8979(99)07803-2].