Hydrothermal spring systems may well have been present on early Mars and could have served as a habitat for primitive life. The integrated instrument suite of the Athena Rover has, as a component on the robotic arm, a Mossbauer spectrometer. In the context of future Mars exploration we present results of Mossbauer analysis of a suite of samples from an iron-rich thermal spring in the Chocolate ...

Mossbauer studies of the ubiquitous protein molecule ferritin and its synthetic "biomimic" polysaccharide iron complex (pIC) exhibit an anomaly in the Mossbauer spectrum wherein the recoil free fraction orf-factor has a sharp drop with respect to temperature as the temperature rises above 30 K for mammalian ferritin and 60 K for PIC. The anomaly coincides with the disappearance ofhyperfme split...

The well-known dependence on preparation conditions of the microstructural polymorphism in nc networks is often also reflected in their magnetic properties. This is particularly evident for non-metallic nc materials where superexchange coupling dominates. The latter is very sensitive to slight variations in bond lengths and angles. For example. this counterplay of local structural and magnetic ...

VIII VI IV Aenigmatite, Na4 (Fe2 +,Ti,Fe 3 +) 1 2 (SiFe 3 +) 12 0 40 , is a common constituent of sodium-rich alkaline igneous rocks and is classified as an open-branched single-chain silicate, whose structure is closely related to that of sapphirine. The first Mossbauer spectra of three valid aenigmatite specimens were recorded and the detailed crystal chemistry were obtained. In the Mossbauer...

Slow (zero field)paramagnetic relaxation is reported for undiluted tetrahedral ferrous monomers for the first time. The Mossbauer spectra of Fe(2,9 di-CH3-phenanthroline)(NCS)2 and Fe(2,9 di-CH3 4,7 di-(j>-phenanthroline) (NCS)2 exhibit magnetic hyperfine splitting in the range 20 K to 1.6 K while the corresponding chlorides are rapidly relaxing paramagnets at all temperatures in zero field. Lo...

Summarised here are the conclusions of an investigation by differential thermal analysis, magnetic susceptibility, Mossbauer spectroscopy, electrical conductivity and thermoelectric power on single crystal Fe0.996S. There is an increase in conductivity both parallel and perpendicular to the c-axis by a factor 102 at Ta (420 K). At low temperature the I. S. is characteristic of a non-metal but i...