Nota de FísicaPublicado
Domain and Domain Walls NMR Spectra in RCo2 Intermetallic Compounds
I. S. Oliveira; O. A. P. Tavares
1996
Dados da publicação
- Autores
- I. S. Oliveira; O. A. P. Tavares
- Tipo
- Nota de Física
- Status
- Publicado
- Data de publicação
- 1996
- Descrição
- NMR signals in ferromagnets originate from domains and domain walls. The technique has the ability to distinguish signals originating from these two regions, through the selection of the radiofrequency (RF) power level applied to the sample. The dependence of the spin echo amplitude upon the RF field intensity can give information on magnetic properties such as domain walls mobility, distribution of local magnetic anisotropies, etc. NMR spectra obtained under different RF intensities allow the investigation of different regions of the samples. In this paper we have applied this technique to the study of the spin-echo amplitude and of the spectra of <math>^{59}Co\,\!</math> in the series of the Laves phase intermetallic compounds <math>RCo_2\,\!</math>, where R = Gd, Dy, Tb at 4.2 K, as a function of the RF field. The results were analyzed according to a model which takes into account several features characteristic of ferromagnetic powdered samples. These include the distribution of the direction of the hyperfine field in respect to the RF field, the variation of the enhancement factor within the domain-walls, the distribution of wall areas, etc. The analysis suggests that whereas in <math>TbCo_2\,\!</math> the NMR signals come purely from domain walls, in <math>DyCo_2\,\!</math> they come mainly from domains. <math>GdCo_2\,\!</math> behaves as an intermediate case where there exists a mixture of contributions to the NMR signals. In this case we were able to observe and measure separately the NMR spectra of nuclei from domains and domain walls.
- Ano
- 1996
- Número
- CBPF-NF-056/96
- Vínculo com tese
- Não
- Vínculo com bolsa
- Não