Cell dimensions and antiferromagnetism of lunar and terrestrial ilmenite single crystals

Journal of Physics and Chemistry of Solids
By: , and 

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Abstract

X-Ray diffraction and anisotropic magnetic measurements have been made on single crystals of lunar ilmenite and on terrestrial ilmenite from Bancroft, Ontario, Canada and the Ilmen Mountains, U.S.S.R. The elongated c-axis of lunar ilmenite, previously reported, is confirmed by new measurements. The shorter c-axis found in terrestrial specimens is ascribed to Fe3+ substitution for Ti4+ in the titanium layer. Magnetic measurements on the same specimens show that, in agreement with the Ishikawa-Shirane et al. model, the initial shortening of the c-axis by the above substitution of small amounts of Fe3+ (<8%) causes an increase in Fe2+−Fe2+ exchange coupling through Fe3+ in the titanium layer that lowers the Néel transition temperature. The Weiss temperatures and other magnetic parameters confirm this model proposed by Ishikawa and Shirane et al.
Additional transitions found in one of the terrestrial specimens (Bancroft) have been ascribed to a small amount of an exsolved spinel phase, possibly a solid solution phase of magnetite-ülvospinel. The spinel phase is localized in hematite-rich blebs which exsolved from the host ilmenite-rich phase.
Publication type Article
Publication Subtype Journal Article
Title Cell dimensions and antiferromagnetism of lunar and terrestrial ilmenite single crystals
Series title Journal of Physics and Chemistry of Solids
DOI 10.1016/0022-3697(77)90155-X
Volume 38
Issue 2
Year Published 1977
Language English
Publisher Elsevier
Description 9 p.
First page 115
Last page 123
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