Physics NotePublished
NMR Measurements in Milled and Intermetallic Compounds
C. V. B. Tribuzy; A. Biondo; C. Larica; K.M.B. Alves; A. P. Guimarães
1998
Publication details
- Authors
- C. V. B. Tribuzy; A. Biondo; C. Larica; K.M.B. Alves; A. P. Guimarães
- Type
- Physics Note
- Status
- Published
- Publication date
- 1998
- Description
- We have used the nuclear magnetic resonance technique to study the magnetic and structural properties of the Gd-Co and Gd-Fe metallic systems, starting with the C15 Laves phase intermetallic compounds, and submitting them to a high energy milling process. This leads to the amorphization of the samples, as determined by the X-ray diffraction spectra. For the Gd-Co system the NMR study used the <math>^{59}Co\,\!</math> nucleus; in the Gd-Fe system, <math>{}^{155,157}Gd \,\!</math> and <math>^{57}Fe\,\!</math> were used. Both systems showed segregation of the pure elements, after a few hours of milling. In the Gd-Co system, a single line, of increasing width, was observed in the <math>^{59}Co\,\!</math> spectrum. In the Gd-Fe system, the<math>^{155}Gd \,\!</math> and <math>^{157}Gd\,\!</math> resonances show three lines, arising from electric quadrupole interaction. With increasing milling time, the lines broaden, and extra lines appear attributed to a cubic phase of Gd; this interpretation is supported by the X-ray analysis of the samples. The <math> ^{57}Fe\,\!</math> NMR spectrum of this system also informs on the direction of magnetization of the samples in the early stages of milling. From 1 h to 7 h of milling, a spectrum of a-Fe was observed. The study of the NMR line intensity as a function of radio frequency (r.f.) power in <math>GdCo_2\,\!</math> suggests the existence of regions of the samples with different degrees of disorder. We have observed the persistence of NMR signals from the original intermetallic compounds in the samples with up to 10 h and 7 h of milling, respectively, for <math>GdCo_2\,\!</math> and <math>GdFe_2\,\!</math>.
- Year
- 1998
- Number
- CBPF-NF-079/98
- Linked to a thesis
- No
- Linked to a grant
- No