Аннотация:The magnetic properties of rare-earth intermetallics RFe11Ti (R = Ho, Er and Tm) were studied. The crystal-field and exchange parameters are determined for the single-crystalline compound by analyzing the experimental magnetization curves obtained in magnetic fields of up to 60 T. A comparison of the theoretical and experimental data was performed, ascertaining their consistency. By using the calculated parameters we succeeded in modeling theoretical magnetization curves for HoFe11Ti, ErFe11Ti and TmFe11Ti up to 200 T and to study in detail the transition from ferrimagnetic to a ferromagnetic state in the applied magnetic field.