M枚ssbauer spectroscopy of <sup>57sup>Fe in 伪-Al<sub>2sub>O<sub>3sub> following implantation of <sup>57sup>Mn<sup>*sup>
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- 作者：H. P. Gunnlaugsson (1) hpg@phys.au.dk
R. Mantovan (2)
T. E. M酶lholt (3)
D. Naidoo (4)
K. Johnston (5)
H. Masenda (4)
K. Bharuth-Ram (6)
G. Langouche (7)
S. 脫lafsson (3)
R. Sielemann (8)
G. Weyer (1)
Y. Kobayashi (9)
the ISOLDE collaboration (5) - 关键词：Emission M枚ssbauer spectroscopy – ; Al<sub>2sub>O<sub>3sub> – ; <sup>57sup>Fe – ; <sup>57sup>Mn
- 刊名：Hyperfine Interactions
- 出版时间：June 2010
- 出版年：2010
- 期刊代码：18_03043843
- 类别：cp
- 卷：198
- 期：1-3
- 页码：5-13
- 数据来源：sp
摘要
The valence state and annealing reactions of Mn/Fe in single crystalline α-Al<sub>2sub>O<sub>3sub> have been determined following low fluence (<10<sup>12sup> cm<sup> − 2sup>) 60 keV implantations of <sup>57sup>Mn<sup> + sup> (T<sub>1/2sub> = 1.5 min) and emission M枚ssbauer spectroscopy on the <sup>57m sup>Fe daughter nuclei in the temperature range from 110–700 K. At 110 K, most probe atoms are found in the Fe<sup>2 + sup> state in amorphous surroundings due to the implantation damage. A fraction of the Fe is found in cubic environment, possibly nano-precipitates of η-Al<sub>2sub>O<sub>3sub>. This site is found to disappear from the spectra above 500 K. Annealing of the damage sites at increasing temperatures leads first to increased incorporation of the probe atoms as Fe<sup>3 + sup> on Al sites, and, above room temperature, also as Fe<sup>4 + sup>. The Fe<sup>3 + sup> sub-spectrum is masked by slow paramagnetic relaxations following a T<sup>2sup> dependence, as expected for a two-phonon Raman process. Our data is consistent with data from <sup>57sup>Co and <sup>57sup>Fe implantations, suggesting a general increase in the average Fe valence state with lower implantation dose and negligible annealing reactions at room temperature.