POSSIBLE FERRIMAGNETIC COUPLING IN LIGHT-RARE-EARTH TRANSITION-METAL INTERMETALLIC COMPOUNDS

The possibility of fenimagnetic coupling between the magnetic moments of the light-rare-earth (Nd, Pr) ions and of the transition-metal (Fe) ions in NdrGa3Fe11- and Pr6Ga3Fe11-based compounds is deduced from the high-field magnetization curves measured at 4.2 K on magnetically aligned and on free-powder samples and from the temperature dependence of the magnetization. The ferrimagnetic coupling is very weak: at 4.2 K, the rare-earth moments and the transition-metal moments can be forced to ferromagnetic alignment by application of an external magnetic field of about 4 T. Generally, in intermetallic compounds, the magnetic coupling is ferromagnetic between light-rare-earth and transition-metal ions and ferrimagnetic between heavy-rare-earth and transition-metal ions. The present results suggest that in some crystal structures ferrimagnetic coupling also may exist in the compounds formed by light-rare-earth and transition-metal elements.