Electric field gradient in biotite mica

Chandra, Ramesh; Lokanathan, S.

doi:10.1002/pssb.2220830130

Cited by 30 publications

(23 citation statements)

References 5 publications

(1 reference statement)

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“…5 we plot the intensity ratios for FeZ+/cis reported by Chandra and Lokanathan (1977) Chandra and Lokanathan (1977)) in two planes containing e'. The dashed line represents the calculated reduced intensity for a uniaxial EFG athan was only 0.05 mm thick so that the total thickness in terms of iron content would only be about 3 mg iron cm-2.)…”

Section: Discussionmentioning

confidence: 99%

“…Specifically, the space group is not given and no attempt is made to identify crystal axes. Chandra and Lokanathan (1977) provide reasonably extensive intensity data in two planes containing the normal to the basal plane (which we shall hereafter designate c', to distinguish it from c* in the (known) C 2/m space group). They claim that their crystal is "hexagonal" since a hexagonal pattern of X-ray reflections is obtained for irradiation along c'.…”

Section: Discussionmentioning

confidence: 99%

“…3 a, b), thickness and polarisation corrections do not shift the positions of turning points in the reduced areas vs rotation angle plots. Chandra and Lokanathan (1977) studied a crystal plate of biotite with dimensions (3 x 2 x 0.005) cm. X-ray diffraction patterns with the radiation normal to the basal plane produced a sharp hexagonal pattern of reflections and the crystal was, therefore, taken to be of hexagonal symmetry.…”

Section: Discussionmentioning

confidence: 99%

“…There have been several papers which describe attempts to measure the electric field gradient (EFG) tensor in biotites or which describe EFG measurements as part of magnetic studies on biotites (Chandra and Lokanathan 1977;Ballet and Coey 1982;Townsend and Longworth 1985). Chandra and Lokanathan describe measurements on a single crystal of biotite said to be "hexagonal" (possibly of the rather uncommon hexagonal polytype, 1H) and report a near uniaxial EFG with the unique axis aligned along, or near the normal to the basal plane of the crystal.…”

Section: Introductionmentioning

confidence: 98%

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Single crystal M�ssbauer studies of 1M biotite

Aldridge¹,

Finch²,

Gainsford³

et al. 1991

Phys Chem Minerals

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Abstract. Electric field gradient (EFG) measurements forFe z + in the cis-and trans-sites of a large single crystal of trioctahedral biotite of the 1M polytype are described. Attempts to apply thickness and polarisation corrections are outlined. The measured EFG's are distinctly rhombic: t1=0.28 and 0.42 respectively for the cis-and transsites and the EFG principal directions lie approximately along the crystallographic axes. For the cis-site V~ lies close to the normal to the basal plane while for the transsite V~ lies close to this direction.

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 98%

See 2 more Smart Citations

Single crystal M�ssbauer studies of 1M biotite

Aldridge¹,

Finch²,

Gainsford³

et al. 1991

Phys Chem Minerals

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“…Des etudes de ce type ont d6jA 8th rnenees sur des micas et argiles [3,4], elles ont permis de determiner partiellement les directions principales du gradient de champ klectrique.…”

Section: Introductionunclassified

Etude du gradient de champ électrique dans la muscovite par spectrométrie Mössbauer du fer

Bonnin¹,

Müller²

1981

Physica Status Solidi (b)

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La spectrombtrie Mossbauer eat utilisbe pour 1'6tude du Fez+ dans la couche octahdrique des micas. Dans le cas qui nous occupe, il s'agit d'un monocristal de muscovite. L'analyse des spectres en fonction des angles entre la direction des y incidents et les axes cristallographiques permet de trouver les directions principales du gradient de champ Blectrique. Les axes du feuillet ne sont pas Bquivalents, lea spectres sont symbtriques par rapport au plan a, c* et non symbtriques par rapport au plan b, c*. Nous montrons que la direction principale du gradient de champ Blectrique est proche du plan a, b du cristal et fait un angle de 45" avec l'axe b. Les directions du gradient de champ Blectrique trouvBes sont comparBes ii. la symBtrie locale du site M2 et aux valeurs trouvbes par le calcul dans un modhle ii. charges ponctuelles.Mossbauer spectrometry is used for the study of Fez+ in the octahedral layer of mica. I n that case, i t concerns a single crystal of muscovite. The study of the spectra which depend on the angles between the incident y-rays and, the crystallographic axes makes it possible t o find the directions of the electric field gradient. The layer axes are not equivalent; the spectra are symmetric with regard to the a, c* plane. It is shown that the main direction of the electric field gradient is near the a, b plane and the angle between this direction and the b axis is about 45". The electric field gradient directions found are compared with those found by the point charge model and the local symmetry of the M, site.

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Search for Anisotropy of Mössbauer Absorption in Biotite

Chandra

Tripathi

Lokanathan

1978

Physica Status Solidi (b)

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A search for anisotropy of Mossbauer factor f in biotite single crystal is made by observing the angular variation of Mossbauer y-absorption directed at various angles to the normal to the plane of the sheet and also by looking for the Goldanskii-Karyagin effect in the powdered specimen. It is suggested that the absence of any detectable anisotropy of the f-values in biotite, and indeed in other Fe containing compounds, in general, is possibly due to the large value of the f-fraction. This is in contrast to tin-and rare-earth compounds where such anisotropy is detectable even a t room temperatures.Es wird die Anisotropie des MoBbauerfaktors f in Biotit-Einkristallen mittels der Beobachtung der Winkeliinderung der MoBbauerabsorption von y-Strahlen, die unter verschiedenen Winkeln senkrecht zur Ebene der Pliittchen gerichtet sind, sowie durch die Beobachtung des Goldanskii-Karyagin-Effects in pulverisierten Proben untersucht. Es wird angenommen, daB das Fehlen jeder nachweisbaren Anisotropie des f-Faktors in Biotit und tatsiichlich auch in anderen Fehaltigen Verbindungen im allgemeinen wahrscheinlich durch den groBen Wert des f-Anteils verursacht wird. Dies steht im Gegensatz zu Zinn-und Seltenen-Erd-Verbindungen, wo derartige Anisotropien sogar bei Zimmertemperatur nachweisbar sind.

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Electric field gradient in biotite mica

Cited by 30 publications

References 5 publications

Single crystal M�ssbauer studies of 1M biotite

Single crystal M�ssbauer studies of 1M biotite

Etude du gradient de champ électrique dans la muscovite par spectrométrie Mössbauer du fer

Search for Anisotropy of Mössbauer Absorption in Biotite

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