Site Occupancy Determination in Th2Zn17- and TbCu7-types Sm2Fe17-xCox Compounds using Synchrotron Resonant Diffraction.
Thomas BartoliJean-Marc JoubertKarine ProvostErik ElkaimValérie Paul-BoncourJudith MonnierJacques MoscoviciLotfi BessaisPublished in: Inorganic chemistry (2021)
Sm2Fe17 compounds are high-performance permanent magnets. Cobalt substitution allows us to further improve their magnetic properties. Depending on the thermal treatment, cobalt-substituted compounds can be synthesized either in the TbCu7 (disordered) or in the Th2Zn17 (ordered) structure type. Rietveld refinement of the number of transition metal dumbbells replacing rare-earth atoms from synchrotron powder diffraction data shows that the TbCu7 disordered structure has the same composition as the ordered one (a transition metal-to-rare earth ratio of 8.5). Then, cobalt site occupancies have been determined in both structures using synchrotron resonant (anomalous) diffraction. Cobalt is found to be absent from the dumbbell sites. The diffraction results are confirmed by Mössbauer spectroscopy.
Keyphrases
- transition metal
- metal organic framework
- reduced graphene oxide
- crystal structure
- electron microscopy
- carbon nanotubes
- high resolution
- heavy metals
- molecularly imprinted
- electronic health record
- gold nanoparticles
- big data
- energy transfer
- machine learning
- artificial intelligence
- deep learning
- replacement therapy
- aqueous solution
- solid state
- simultaneous determination