ITN

Mössbauer Spectroscopy Laboratory

Building for Cryogenic Techniques

Mössbauer spectroscopy is a nuclear technique that has been developed in ITN for applications in ITN coordinated research on Solid State Science and Earth Sciences. This facility has also been supporting, since its very first steps, research programs from other national or foreign Research Institutes and Universities. This interaction with other institutions has always been performed on the basis of scientific collaboration and formation of young scientists (graduate and post-graduate students) since expert interpretation of the Mössbauer spectra based on the electronic structure of the studied samples is necessary.

Main Equipment

Two Mössbauer Spectrometers, in either transmission or back-scattering geometry. These spectrometers may be coupled to a continuous-flow liquid-He cryostat or a bath cryostat equipped with a superconducting split-pair magnet enabling studies with the absorber in the temperature range 2-300 K and under magnetic fields up to 5 T.

Sources existing and currently used are for ⁵⁷Fe and ¹⁵¹Eu Mössbauer spectroscopy. Other sources such as ^119mSn may be acquired if a research program justifies it. In other cases, as for same rare earths, the sources can be prepared at the RPI.

Examples of on-going research in Materials Science, Biotechnology and Earth Sciences

• Ternary intermetallics of A-Fe-M systems (A=rare-earth, U; M = Al, Si, Ga, Ge, Sn). Structural characterization and investigation of the magnetic properties of the Fe sublattices.
• Mixed-conducting oxide materials for high-temperature electrochemical devices: electrodes of solid oxide fuel cells, ceramic membranes for partial oxidation of hydrocarbons. Study of the Fe oxidation state and coordination (collaboration with the Univ. of Aveiro).
• Thin films formed by Fe implantation in Al. Identification of the crystallographic sites occupied by Fe and of the Fe-containing phases
• Molecule-based magnets. Magnetic properties of Fe (collaboration with the Univ. of Valencia, Spain).
• Metalloproteins. Electronic state of Fe; correlation between magnetic properties and structural/functional characteristics of the proteins (collaboration with the Fac. Sciences of the Univ. Lisbon).
• Mineral chemistry. Oxidation state and distribution of Fe atoms in different crystallographic sites. Applied to the establishment of metallogenetic models for ore-forming systems (collaboration with the Fac. Sciences of the Univ. of Lisbon).
• Alteration mechanisms of rocks used as building materials. Contribution to the conservation of historical buildings (collaboration with the Technical Univ. of Lisbon).