- Tytuł:
- Magnetic Properties of Mn-Doped Amorphous $SiO_2$ Matrix
- Autorzy:
-
Milivojević, D.
Babić-Stojić, B.
Jokanović, V.
Jagličić, Z.
Makovec, D. - Powiązania:
- https://bibliotekanauki.pl/articles/1503690.pdf
- Data publikacji:
- 2011-08
- Wydawca:
- Polska Akademia Nauk. Instytut Fizyki PAN
- Tematy:
-
75.50.Lk
75.47.Lx
75.50.Tt - Opis:
- Samples of Mn-doped amorphous $SiO_2$ matrix with manganese concentration 0.7 and 3 at.% have been prepared by a sol-gel method. Transmission electron microscopy analysis has shown that the samples contain agglomerates of amorphous silica particles 10 - 20 nm in size. Two types of Mn-rich particles are dispersed in silica matrix, smaller nanoparticles with dimensions between 3 and 10 nm, and larger crystalline areas consisting of aggregates of the smaller nanoparticles. High-temperature magnetic susceptibility reveals that dominant magnetic phase at higher temperatures is $λ-MnO_2$. At temperatures below $T_{C}$=43 K strong ferrimagnetism originating from the minor $Mn_3O_4$ phase masks the relatively weak magnetism of $λ-MnO_2$. Magnetic field dependence of the maximum in the zero-field-cooled magnetization for both the samples in the vicinity of 40 K, and a frequency shift of the real component of the AC magnetic susceptibility in the sample with 3 at.% Mn suggest that the magnetic moments of the smaller $Mn_3O_4$ nanoparticles with dimensions below 10 nm are subject to thermally activated blocking process just below the Curie temperature $T_{C}$. The low-temperature maximum in the zero-field-cooled magnetization observed for both the samples below 10 K indicates possible spin glass freezing of the magnetic moments in the geometrically frustrated Mn sublattice of the $λ-MnO_2$ crystal structure.
- Źródło:
-
Acta Physica Polonica A; 2011, 120, 2; 316-321
0587-4246
1898-794X - Pojawia się w:
- Acta Physica Polonica A
- Dostawca treści:
- Biblioteka Nauki
Artykuł