Previous page     Contents     Next page

The Mössbauer technique is ideally suited to quantifying the ferric iron content of small samples such as those produced by the laser-heated diamond-anvil-cell (LHDAC). We are using this technique to compare the ferric iron content of silicate perovskite produced from the same synthetic pyroxene by two prominent European LHDAC laboratories. One of these laboratories uses a YAG laser for heating the sample in a solid pressure medium and the other uses a carbon dioxide laser for heating the sample in both argon and a solid medium. Our Mössbauer measurements show that all the samples of perovskite produced in the LHDAC contained less than 5% ferric iron. These results indicate that the ferric iron content of the perovskite is not influenced by either heating method or pressure medium in the LHDAC.

The only significant difference in the samples is that one of the YAG laser heated samples had about 5% of iron metal in it. This sample was loaded into the DAC under argon instead of the usual atmosphere of air. Thus, this solid-media LHDAC can produce reduced phases in silicates that are loaded under argon, consistent with results of a detailed study of electrical conductivity in this solid medium, YAG LHDAC.