- Tytuł:
- Positron Annihilation in $MnFe_2O_4$/MCM-41 Nanocomposite
- Autorzy:
-
Wiertel, M.
Surowiec, Z.
Gac, W.
Budzyński, M. - Powiązania:
- https://bibliotekanauki.pl/articles/1339369.pdf
- Data publikacji:
- 2014-03
- Wydawca:
- Polska Akademia Nauk. Instytut Fizyki PAN
- Tematy:
-
78.70.Bj
34.80.Lx
78.67.Bf
62.23.Pq
68.43.-h
75.50.Gg
78.47.D- - Opis:
- In the paper results of studies of $MnFe_2O_4$/MCM-41 nanocomposites have been presented. The influence of manganese ferrite loading on changes of porous properties of mesoporous MCM-41 structure was studied by means of $N_2$ sorption/desorption method and positron annihilation lifetime spectroscopy. Disappearance of the longest-lived ortho-positronium component ($τ_5$) of pure MCM-41 mesoporous material in the positron annihilation lifetime spectra of $MnFe_2O_4$/MCM-41 measured in vacuum is a result of either o-Ps quenching or the Ps inhibition mechanism. Filling of pores in the studied nanocomposites by air at ambient pressure causes partial reappearance of the ($τ_5$) component except for the sample with maximum ferrite content. Both the ($τ_5$) component lifetime and intensity are suppressed together with increasing $MnFe_2O_4$ content by chemical quenching and inhibition of Ps formation occur. Observed anti-quenching effect of air is a result of two processes: neutralization of some surface active centres acting as inhibitors and considerably weaker paramagnetic quenching by $O_2$ molecules.
- Źródło:
-
Acta Physica Polonica A; 2014, 125, 3; 793-797
0587-4246
1898-794X - Pojawia się w:
- Acta Physica Polonica A
- Dostawca treści:
- Biblioteka Nauki
Artykuł