W. G. Stirling | Searcharxiv

arXiv2007

Profile of the U 5f magnetization in U/Fe multilayers

Recent calculations, concerning the magnetism of uranium in the U/Fe multilayer system have described the spatial dependence of the 5f polarization that might be expected. We have used the x-ray resonant magnetic reflectivity technique to obtain the profile of the induced uranium magnetic moment for selected U/Fe multilayer samples. This study extends the use of x-ray magnetic scattering for induced moment systems to the 5f actinide metals. The spatial dependence of the U magnetization shows that the predominant fraction of the polarization is present at the interfacial boundaries, decaying rapidly towards the center of the uranium layer, in good agreement with predictions.

cond-mat.other↗

arXiv2003

Kinetic energy of He atoms in liquid $^4$He-$^3$He mixtures

Deep Inelastic Neutron Scattering measurements on liquid $^3$He-$^4$He mixtures in the normal phase have been performed on the VESUVIO spectrometer at the ISIS pulsed neutron source at exchanged wavevectors of about $q \simeq 120.0$ Å$^{-1}$. The neutron Compton profiles J(y) of the mixtures were measured along the $T=1.96$ K isotherm for $^3$He concentrations, $x$, ranging from 0.1 to 1.0 at saturated vapour pressures. Values of kinetic energies, $ $, of $^3$He and $^4$He atoms as a function of $x$, $ (x)$, were extracted from the second moment of J(y). The present determinations of $ (x)$ confirm previous experimental findings for both isotopes and, in the case of $^3$He, a substantial disagreement with theory is found. In particular $ (x)$ for the $^3$He atoms is found to be independent of concentration yielding a value $ _3(x=0.1)\simeq 12 K $, much lower than the value suggested by the most recent theoretical estimates of approximately 19 K .

cond-mat.mtrl-sci↗