ArticlesMossbauer Studies

Mössbauer Effect and High-Voltage Electron Microscopy of Pyroxenes in Type B Samples

Science  30 Jan 1970:
Vol. 167, Issue 3918, pp. 686-688
DOI: 10.1126/science.167.3918.686

Abstract

Site occupancy numbers for ferrous iron, magnesium, and calcium at the Ml and M2 sites in lunar clinopyroxenes are estimated from nuclear gamma-ray resonant absorption spectra of 57Fe. The cation distribution is ordered; calcium and magnesium prefer M2 and Ml, respectively. The distribution corresponds to an equilibrium at a temperature lower than 680°C. Crystals cleaved and sectioned by diamond-knife ultramicrotomy were examined by high-voltage (200 kv) electron microscopy and diffraction. Uniform 300-to 600-A-wide bands that correspond to single crystal domains were found. Correlation of the bands with magnetic ordering at low temperatures is considered.

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