M. Rots

Valency of rare earths in R In-3 and R Sn-3: ab initio analysis of electric-field gradients

In

What density-functional theory can tell us about the spin-density wave in Cr

R{\mathrm{In}}_{3}

In-beam study of the level crossing resonance on the 4 μs 2 9+ isomer of69Ge in a Zn single crystal

and

High resolution TDPAC work using CsF and BaF2 fast detectors

R{\mathrm{Sn}}_{3}

Nuclear-level mixing resonances on low-temperature oriented nuclei

the rare earth (R) is trivalent, except for Eu and Yb, which are divalent. This was experimentally determined in 1977 by perturbed angular correlation measurements of the electric-field gradient on a

Formulation of angular correlation and distribution experiments in the presence of a texturized hyperfine interaction

{}^{111}\mathrm{Cd}

Interface and structure characterization of co/re multilayers using rbs channeling and hyperfine interactions

impurity. At that time, the data were interpreted using a point charge model, which is now known to be unphysical and unreliable. This makes the valency determination potentially questionable. We revisit these data, and analyze them using ab initio calculations of the electric-field gradient. From these calculations, the physical mechanism that is responsible for the influence of the valency on the electric-field gradient is derived. A generally applicable scheme to interpret electric-field gradients is used, which in a transparent way correlates the size of the field gradient with chemical properties of the system.

The magnetism of UX3 compounds (X = In, Pb, Ga) from symmetry considerations and perturbed-angular-correlation spectroscopy

The energy-versus-volume curve of the spin-density wave (SDW) in body-centred-cubic Cr is calculated with the density functional theory/full-potential linearized augmented plane wave (DFT/FLAPW) method using the generalized gradient approximation (GGA). The predicted ground state is not the SDW, in contrast to an earlier FLAPW calculation. A conjecture is formulated that the widely varying results of the local density approximation (LDA) and GGA - and of different solution methods - can be scaled by the size of the calculated moment. As a consequence, experimentally relevant properties of the SDW can be calculated by tuning the moment. The implications of these results for the ability of DFT to describe Cr are discussed.

Magnetic anisotropy studied with PAC: magnetic hyperfine fields on 111Cd in bcc iron/cobalt multilayers

The time-integral angular distribution was measured as a function of an external magnetic field for γ-rays from the 398 keV29+ state of69Ge populated by bombarding a Zn single crystal with a natural α-beam from a cyclotron. Clear resonances of dispersion as well as Lorentz type having a narrow width consistent with the natural width (τ=4 μs) were observed at Bres=9.15 kG corresponding to the first level-crossing resonance of the29+ state due to the combined collinear magnetic and quadrupole interactions. The effects of noncollinearity were also demonstrated and compared with theory. As an application of this resonance method, the temperature dependence of the quadrupole interaction frequency was measured.

A comparative study of CoRe superlattices sputtered on glass and Si substrates by grazing angle of incidence RBS, HRTEM, PAC, magnetic and transport properties studies

Abstract Barium fluoride and cesium fluoride inorganic scintillators offer excellent timing, reasonable energy resolution and good gamma ray detection efficiencies. These characteristics are very desirable for accurate time differential perturbed angular correlation/distribution (TDPAC/D) experiments and enables one to extend the TDPAC/D techniques for the study of many interesting solid state aspects such as near neighbour interactions, conduction electron polarization, short and long range ordering etc. The performance of these detectors is compared with the commonly used ones and their potential for new solid state applications is demonstrated by means of some illustrative examples.