First natural hexaferrite with mixed β'-ferrite (β-alumina) and magnetoplumbite structure from Jabel Harmun, Palestina

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Marco E. Ciriotti
Messaggi: 24698
Iscritto il: ven 25 giu, 2004 11:31
Località: via San Pietro, 55 I-10073 Devesi/Cirié TO - Italy
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First natural hexaferrite with mixed β'-ferrite (β-alumina) and magnetoplumbite structure from Jabel Harmun, Palestina

Messaggio da Marco E. Ciriotti » lun 27 nov, 2017 16:56

Prossima pubblicazione.

Referenza:
▪ Galuskin, E.V., Galuskina, I.O., Widmer, R., Armbruster, T. (2018): First natural hexaferrite with mixed β'-ferrite (β-alumina) and magnetoplumbite structure from Jabel Harmun, Palestinian Autonomy. European Journal of Mineralogy, 30, (in press).

Abstract:
Ferrites of K and Ba close in composition to the known synthetic compounds KFe22+Fe153+O25 and BaMg2Fe163+O27 were found in a thin vein, filled with magnesioferrite and khesinite, in pyrometamorphic flamite–gehlenite hornfels of the Hatrurim Complex, Palestinian Autonomy. Both ferrites are characterized by a modular structure composed of 5-layered spinel (S) blocks interstratified with R-blocks. The R-modules of K-ferrite are of the β-alumina type whereas those in Ba-ferrite are of the magnetoplumbite type. Rare grains of K-Ba-ferrite of intermediate composition with the empirical crystal chemical formula (EPMA): (KO:57BaO:38NaO:05)Σ1(Fe3+14.08Mg1:42AlO:80ZnO:59NiO:16CaO:14CuO:09MnO:03TiO:03SiO:02)Σ17:36O25:54, were also discovered. The structure of the natural mixed potassium-barium ferrite was investigated by single-crystal X-ray diffraction. The hexagonal space-group symmetry (P6m2, Z = 2) with a = 5.9137(2) and c = 33.1450(15)Å is different to that (P63/mmc) of the end-members and yields alternate stacking of β-alumina type KMg2Fe15O25 and magnetoplumbite type BaMg2Fe16O27 “supermodules”, each extending ½ of the unit cell along c. Raman spectroscopic study confirms the mixed character of K-Ba-ferrite structure. K-Baferrite formed at non-equilibrium conditions and may be interpreted as an example of a nano-dissipative structure.
Marco E. Ciriotti

«Things are interesting only in so far as they relate themselves to other things»

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Marco E. Ciriotti
Messaggi: 24698
Iscritto il: ven 25 giu, 2004 11:31
Località: via San Pietro, 55 I-10073 Devesi/Cirié TO - Italy
Contatta:

First natural hexaferrite with mixed β'-ferrite and magnetoplumbite structure from Jabel Harmun, Palestina

Messaggio da Marco E. Ciriotti » gio 20 set, 2018 12:00

Pubblicazione effettuata.

Referenza:
▪ Galuskin, E.V., Galuskina, I.O., Widmer, R., Armbruster, T. (2018): First natural hexaferrite with mixed β'-ferrite (β-alumina) and magnetoplumbite structure from Jabel Harmun, Palestinian Autonomy. European Journal of Mineralogy, 30, 559-567.

Abstract:
Ferrites of K and Ba close in composition to the known synthetic compounds KFe22+Fe153+O25 and BaMg2Fe163+O27 were found in a thin vein, filled with magnesioferrite and khesinite, in pyrometamorphic flamite–gehlenite hornfels of the Hatrurim Complex, Palestinian Autonomy. Both ferrites are characterized by a modular structure composed of 5-layered spinel (S) blocks interstratified with R-blocks. The R-modules of K-ferrite are of the β-alumina type whereas those in Ba-ferrite are of the magnetoplumbite type. Rare grains of K-Ba-ferrite of intermediate composition with the empirical crystal chemical formula (EPMA): (KO:57BaO:38NaO:05)Σ1(Fe3+14.08Mg1:42AlO:80ZnO:59NiO:16CaO:14CuO:09MnO:03TiO:03SiO:02)Σ17:36O25:54, were also discovered. The structure of the natural mixed potassium-barium ferrite was investigated by single-crystal X-ray diffraction. The hexagonal space-group symmetry (P6m2, Z = 2) with a = 5.9137(2) and c = 33.1450(15)Å is different to that (P63/mmc) of the end-members and yields alternate stacking of β-alumina type KMg2Fe15O25 and magnetoplumbite type BaMg2Fe16O27 “supermodules”, each extending ½ of the unit cell along c. Raman spectroscopic study confirms the mixed character of K-Ba-ferrite structure. K-Baferrite formed at non-equilibrium conditions and may be interpreted as an example of a nano-dissipative structure.
Marco E. Ciriotti

«Things are interesting only in so far as they relate themselves to other things»

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