Arno Ehresmann

Modification of the exchange bias effect by He ion irradiation

FeNi/FeMn exchange bias samples with a large exchange bias field at room temperature have been prepared. Upon irradiation with He ions, both the exchange bias field and the coercive field are modified. For low ion doses the exchange bias field is enhanced by about 70%. Above a threshold dose of 0.3/spl middot/1/sup 15/ ions/cm/sup 2/, the exchange bias field decreases continuously as the ion dose increases. The observed modifications can be explained in terms of defect creation acting as pinning sites for domain walls and atomic intermixing.

Observation and identification of odd XeI Rydberg resonances near 5s-threshold

Photoionization cross sections for the production of main 5s line and some 5p4 5d/6s satellites of XeII in the region of the 5s-photoionization threshold have been measured by photon-induced fluorescence spectroscopy (PIFS) with extremely high primary resolution. The most pronounced features in the experimental spectra were interpreted on the basis of theoretical calculations.

Alignment and orientation of the ionic states of rare‐gas atoms populated by resonant Auger effect

A short review of theoretical and experimental papers devoted to the investigation of the alignment, A20, and orientation, O10, of ions after the decay of atomic resonances is presented. Special attention is paid to the dependence of A20 and O10 on the exciting‐photon energy. The possible ways for improving the theoretical description of the resonant Auger effect are also discussed.

FINE-STRUCTURE SELECTIVE PREDISSOCIATION OF O2

The OI emission cross section and the absorption cross section of O2 were investigated near the threshold for neutral dissociation into the OI state with a very narrow bandwidth (0.9 meV) of the exciting radiation. The fine-structure components of vibrational levels were resolved for the first time in the emission cross section. A certain degree of selectivity in the population of fine-structure components was observed.