Magnetic behavior of trioctahedral micas with different octahedral Fe ordering
This contribution is finalized at the discussion of the magnetic structure of two samples, belonging to phlogopite–annite [sample TK, chemical composition IV (Si 2.76 Al 1.24 ) VI (Al 0.64 Mg 0.72 Mn 0.03 Ti 0.15 ) (K 0.96 Na 0.05 ) O 10.67 (OH) 1.31 Cl 0.02 ] and polylithionite–siderophyllite joint...
Saved in:
Published in | Physics and chemistry of minerals Vol. 39; no. 8; pp. 665 - 674 |
---|---|
Main Authors | , , , , |
Format | Journal Article |
Language | English |
Published |
Berlin/Heidelberg
Springer-Verlag
01.09.2012
Springer Nature B.V |
Subjects | |
Online Access | Get full text |
Cover
Loading…
Summary: | This contribution is finalized at the discussion of the magnetic structure of two samples, belonging to phlogopite–annite [sample TK, chemical composition
IV
(Si
2.76
Al
1.24
)
VI
(Al
0.64
Mg
0.72
Mn
0.03
Ti
0.15
) (K
0.96
Na
0.05
) O
10.67
(OH)
1.31
Cl
0.02
] and polylithionite–siderophyllite joints [sample PPB, chemical composition
IV
(Si
3.14
Al
0.86
)
VI
(Al
0.75
Mg
0.01
Mn
0.01
Ti
0.01
Li
1.09
) (K
0.99
Na
0.01
) O
10.00
(OH)
0.65
F
1.35
]. Samples differ for Fe ordering in octahedral sites, Fe
2+
/(Fe
2+
+ Fe
3+
) ratio, octahedral composition, defining a different environment around Fe cations, and layer symmetry. Spin-glass behavior was detected for both samples, as evidenced by the dependency of the temperature giving the peak in the susceptibility curve from the frequency of the applied alternating current magnetic field. The crystal chemical features are associated to the different temperature at which the maximum in magnetic susceptibility is observed: 6 K in TK, where Fe is disordered in all octahedral sites, and 8 K in PPB sample, showing a smaller and more regular coordination polyhedron for Fe, which is ordered in the
trans
-site and in one of the two
cis
-sites. |
---|---|
ISSN: | 0342-1791 1432-2021 |
DOI: | 10.1007/s00269-012-0520-1 |