Studies of119Sb ions adsorbed on ferrimagnetic spinel oxide CoFe2O4 surfaces by means of emission Mössbauer spectroscopy

The chemical states of¹¹⁹Sb⁵⁺ ions hydrolytically adsorbed on spinel type ferrimagnetic oxide CoFe₂O₄ powders are studied by means of emission Mössbauer spectroscopy of the daughter nuclide¹¹⁹Sn. The spectra show a broadening which is attributed to the supertransferred hyperfine magnetic field coming from the magnetically ordered metal ions of the substrate. Distribution of the field is obtained from the spectra and its change with temperature is discussed.     

Deformation band evolution in [110] Al single crystals strained in tension

Several types of deformation bands form during uniaxial extension of Al single crystals for which the tensile axis is initially parallel to [110]. The objectives of the present work are to analyse crystal orientation evolution in the deformation bands and adjoining regions, and to integrate the experimental observations with a crystal mechanics model. The most prominent deformation bands contain secondary slip traces and exhibit crystal rotations consistent with unpredicted slip on a secondary slip system. These special bands of secondary slip (SBSS) become more closely aligned with the tensile axis as extension increases. The evolution of SBSS inclination with extension indicates that SBSS form initially as kink bands and that SBSS boundaries are immobile. SBSS grow during straining by expansion of the volume of material in which secondary slip operates. Deformed matrix (DM) bands are zones between SBSS; primary slip predominates in DM bands. Small intra-DM bands result from spatial variation of the shear amplitudes for the two primary slip systems. The evolution of intra-DM band inclination with extension indicates that intra-DM bands form initially as kink bands and that the band boundaries are mobile, at least to some extent.     

Spatial distribution of YO molecules ejected from laser-ablated YBa2 Cu3 O7−x

One-dimensional imaging laser-induced fluorescence spectroscopy has been used for in-situ measurements of spatial distributions of YO molecules produced during the ArF-laser ablation of YBa₂ Cu₃ O _7–x in vacuum and oxygen gas environment. The time-integrated angular distribution of particles ejected in vacuum has a cos ⁿ form, where 11 <n < 13. When oxygen gas was introduced, YO molecules were confined in a smaller volume, and temporal changes of their spatial distribution were interpreted in terms of blast-wave formation.     

High energy spectroscopy in Ce and La compounds

X-ray photoemission, X-ray photoabsorption and bremmstrahlung isochromat spectroscopy in Ce and La compounds are theoretically analyzed by using the single-site Anderson model incorporated with various final state interactions. Discussions are given on the physical information derived from the analysis and also on similarities and differences in spectral features between metallic and insulating systems.     

Low-Energy Kaon�CNucleon/Nuclei Interaction Studies at DA��NE (SIDDHARTA and AMADEUS Experiments)

The DA??NE electron?Cpositron collider at the Laboratori Nazionali di Frascati of INFN has made available a unique quality low-energy negative kaons ??beam??. The SIDDHARTA experiment used this beam to perform unprecedented precision measurements on kaonic atoms, while the AMADEUS experiment plans to perform in the coming years precision measurements on kaon?Cnuclei interactions at low-energies, in particular to study the kaonic nuclei. The two experiments are briefly presented in this paper.     

Color centers in irradiated MgF2

Abstract

Color centers in rutile-structured MgF₂ single crystals irradiated at 20K/360K by reactor neutrons are investigated spectroscopically at LNT. Four different types of the F-F vacancy bond in MgF₂ are possibly identified to the observed absorption bands as due to the F₂ centers; instead of previous assignments, the 300nm band to the F₂(D_2h), the 325nm band to the F₂(C₁), the 355nm band to the F₂(C_2v), and the 400nm band to the F₂(C_2h) centers.