Magnetic properties of RnI/sub 4/Fe alloys (R = La, Ce, or Y)
Magnetization of several RNi/sub 4/Fe alloys (R = La, Ce or Y) was studied over the temperature region 4 to approx. 300 K and in applied fields up to 21 kOe. Replacement of Ni by Fe in the RNi/sub 5/ systems expands the lattice and produces a significant alteration in magnetic behavior. In contrast with the RNi/sub 5/ systems that do not order magnetically, the RNi/sub 4/Fe alloys develop ferromagnetic order at low temperatures with Curie temperatures ranging from 195 to 270 K. Saturation magnetizations (in ..mu../sub B/ per formula unit at 4 K) were 5.0, 3.3, and 4.0 for R = La, Ce, and Y, respectively. The low moment of CeNi/sub 4/Fe together with its anomalously small unit cell volume strongly suggests that Ce in this alloy is quadripositive. The magnetic behavior of the RNi/sub 4/Fe systems indicates that Fe induces moments on the neighboring Ni atoms, approximately 0.9 ..mu../sub B/Ni/ atoms in the case of LaNi/sub 4/Fe. Below the Curie temperature, magnetization-temperature plots obtained using low field (4 kOe) show a broad maximum for the La system whose origin as yet is not completely clear. The maximum disappears at applied fields approximately 20 kOe, and hence it may arise from increased magnetic hardness at low temperatures.
- Research Organization:
- Pittsburgh Univ., PA (USA). Dept. of Chemistry
- OSTI ID:
- 6324504
- Report Number(s):
- AD-A-157745/1/XAB
- Country of Publication:
- United States
- Language:
- English
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