Magnetic exchange coupling in amorphous Fe 82- xHo xB 18 alloys

Magnetization data of melt-spun amorphous Fe _{82- x}Ho _xB ₁₈ (4⩽ x⩽16) alloys are analyzed using a two-sublattice mean-field theory (MFT) and the exchange interactions are derived. High-field magnetization measurements performed on samples with small net magnetizations give evidence of the occurrence of a magnetic transition, characteristic of a non-collinear rare-earth and transition-metal sublattices structure. Besides, analysis of the non-collinear regime has permitted the evaluation of the intersublattice exchange coupling parameters which are found to be in good agreement with those deduced using a mean-field analysis.