Samarium: magnetic neutron spectroscopic intensities

Abstract

The present work, while specific to Samarium and motivated by recent neutron beam results, serves also to illustrate the largely unexpected richness of neutron electron spectroscopy and its potential for future development as a tool in studies of magnetic materials. In our calculation we have modelled Samarium as a trivalent, isolated magnetic ion and we consider the dependence of the twelve states lowest in energy on the spin-orbit interaction strength. We then calculate the wave vector dependence of the inelast~c structure factors for intra-and inter-multiplet magnetic neutron scattering from the ground state. For ease of comparison with experimental data an intensity profile for a sample incident neutron energy is given.

VLAD for epithermal neutron scattering experiments at large energy transfers

“…At present VESUVIO can detect epithermal neutrons scattered at angles above 20°, which translates into exchange wave vectors and energy transfers of 20 A -1 < q < 200 A -1 and 1 eV< ω < 10 eV, respectively. Experiments in such kinematical range have been performed in the last ten years to successfully investigate condensed matter systems such as hydrogen bond and metal hydrides [2], metals [3], glasses [4] and quantum fluid and solids [5]. Still there is a strong interest into extending the kinematical region to low wave vector transfers (3 A -1 < q < 10 A -1…”

Intermultiplet Crystal-Field Transitions in SmBa2Cu3Guillaume1, Henggeler2, Fürrer3 et al. 1995Phys. Rev. Lett.280120View full textAdd to dashboardCite

“…The splitting between the J multiplets H5y2 and 07/2 ts 128 meV [6]. Figure 4 shows the difference of the normalized spectra observed for SmBa2Cu307 and YBa2Cu 307 in the higher energy range.…”

“…The CEF Hamiltonian (1) was treated with J mixing and intermediate coupling including the ten lowest J multiplets [6]. The Fig.…”

“…Only by the observation of intermultiplet transitions have we been able to determine a reliable set of CEF parameters. It would be highly desirable to extend the present measurements methodically beyond the first-excited J multiplet, however, the corresponding neutron cross sections drastically decrease by more than an order of magnitude [6]. Clearly, the expected advent of very high-intensity pulsed neutron sources will make such experiments feasible.…”

Development of the very low angle detector for epithermal neutron scattering at low momentum transfers

“…Yet there is an interest in extending the range of scattering parameters to the kinematical region of low (3 Å -1 < q < 10 Å -1 ) wave vector transfers coupled to high energy transfer (typically 0.1 eV < ω < 5 eV). In this range -which we call High Inelastic Neutron Scattering (HINS) -new and unique experimental investigations would become possible such as dispersion relations of magnetic materials [6], semiconductors [7], high lying molecular rotational-vibrational states, molecular electronic excitations and electronic levels in solids [8]. HINS experiments require the detection of epithermal neutrons at scattering angles as low as 1°-5°.…”