PRESSURE EFFECTS ON THE MAGNETIC-PROPERTIES OF CE2FE17HX

Alloys of the R(2)Fe(17) series (R = rare earth element) are promising candidates as new magnet materials when C or N atoms are inserted in the structure (3/f.u.). Insertion results in a considerable increase i n Curie temperature, a large enhancement of the magneto-crystalline an isotropy and small increase in the iron magnetisation. Similarly, it w as observed that the parent compounds have most of their fundamental p roperties markedly affected by hydrogen insertion which is easy to con trol up to 5 H/f.u. The case of the anomalous Ce-compound is of a firs t interest. The magneto-volume effects may be correlated to some chang es in the intermediate valence state of Ce, and also to significant in creases of critically short Fe-Fe distances. Magnetic measurements hav e been performed under external pressure. The changes in Curie tempera ture and magnetisation are reverse to those deduced from the cell expa nsion upon H insertion.