| Автор | T V V Costa |
| Автор | V W Vieira |
| Автор | M A B de Araújo |
| Дата выпуска | 1989-11-01 |
| dc.description | The Mössbauer spectra of a powdered sample of the Ibitira meteorite (achondrite) have been obtained at different temperatures, ranging from 4.2 K up to 300 K. X-ray diffraction analysis indicates that the meteorite consists mostly of anorthite (CaAl<sub>2</sub>Si<sub>2</sub>O<sub>8</sub>) and pigeonite [(Mg, Fe, Ca)<sub>2</sub>Si<sub>2</sub>O<sub>6</sub>)]The Mössbauer spectrum at room temperature consists of an asymmetric doublet with parameters characteristic of iron in the oxidation state Fe(II). The asymmetry is due to the overlapping of two quadrupole doublets arising from Fe(II) in the two different crystallographic sites (M1 and M2) of pigeonite. The temperature dependence of the Mössbauer parameters is different for the two sites, so they are clearly distinguishable at low temperatures (<55 K). No magnetic effects were observed between 300 K and 14 K. The spectrum obtained at 4.2 K exhibits magnetic relaxation. The mechanism of relaxation has not yet been deeply investigated. It should probably be spin-spin relaxation as it was recently observed in terrestrial pyroxenes [1]. |
| Формат | application.pdf |
| Издатель | Institute of Physics Publishing |
| Название | Low temperature Mössbauer spectra of the Ibitira meteorite (achondrite) |
| Тип | paper |
| DOI | 10.1088/0031-8949/40/5/022 |
| Electronic ISSN | 1402-4896 |
| Print ISSN | 0031-8949 |
| Журнал | Physica Scripta |
| Том | 40 |
| Первая страница | 702 |
| Последняя страница | 704 |
| Аффилиация | T V V Costa; Departmento de Fisica - UFCe, 60.450 Fortaleza, Brasil |
| Аффилиация | V W Vieira; Departmento de Fisica - UFCe, 60.450 Fortaleza, Brasil |
| Аффилиация | M A B de Araújo; Departmento de Fisica - UFCe, 60.450 Fortaleza, Brasil |
| Выпуск | 5 |
