Field-induced magnetic transitions in Pr2(Co, Fe)17

A study of the different magnetic field-induced transitions has been performed for Pr2Co17-xFex compounds in the temperature range 78-300 K. By using the singular point detection technique, it has been shown that all compounds with x > 0 exhibit at least one field-induced transition, which has been identified as a first-order magnetization process (FOMP). Different types of FOMP (A1, A2, P1) are observed, and the change of the type can be induced by varying either temperature or composition. Intermediate Co-Fe compositions show a P I-type FOMP which persists even above room temperature, while a double transition has been found in iron-rich compounds with x greater than or equal to 13.6. It has also been noticed that, for the particular values of x when a temperature-induced spin reorientation is present, the change from Al to PI type FOMP (or vice versa) exactly occurs at the spin reorientation temperature, with a vanishing critical field value. A comparison with the behavior Of Y2Co17-xFex compounds leads to the conclusion that the contributions of the Pr sublattice are essential for the development of these field-induced transitions (some of which are still present at room temperature), even if it is inferred that the overall anisotropy is mainly determined by the 3d sublattice. (C) 2002 Elsevier Science B.V. All rights reserved.