Crystal Field Levels of Pr³⁺ in PrAl₃ Studied by Inelastic Neutron Scattering

Abstract

The crystal field splitting of the ,H., ground multiplet of the Pr3+ ion in the intermetallic compound PrAl, is investigated by inelastic scattering of thermal neutrons. At several temperatures crystal field transitions are measured by TOF and TAS methods for polycrystalline PrAI,. I n order to decide between crystal field transitions and phonon scattering, the isostructural, nonmagnetic compound LaAI, is also measured. The crystal field parameters and the energy level scheme for the ground multiplet splitting in PrAI, are given.Die Kristallfeldaufspaltung des 3H,-Grundzustandsmultipletts von Pr3+ in der intermetallischen Verbindung PrAI, wird mittels inelastischer Streuung thermischer Neutronen untersucht. Die Kristallfeldiibergiinge in PrAI, werden bei verschiedenen Temperaturen mit Hilfe von Flugzeitund Dreiachsenspektrometer gemessen. Um zwischen Kristallfeldiibergiingen und Phononenstreuung zu unterscheiden, wird die isostrukturelle, nichtmagnetische Verbindung LaAI, ebenfalls untersucht. Die Kristallfeldparameter und das Niveauschema der Aufspaltung des Grundzustandsmultipletts in PrAI, werden angegeben.

Crystal-field excitations in PrAl3and NdAl3at ambient and elevated pressure

“…Moreover, the hexagonal structure allows a change of the lattice parameter ratio c/a under hydrostatic pressure p. We have performed INS experiments for PrAl 3 ( p = 0) and NdAl 3 ( p = 0 and 0.84 GPa) which allowed for an unambiguous determination of the CF parameters. Our data clarify earlier INS studies of the CF in these compounds which resulted either in different possible sets of CF parameters for PrAl 3 [1][2][3][4] or uncertainties about the CF ground state in NdAl 3 [5]. The CF parameters obtained in the present work are examined with regard to extrapolation schemes based on the extended point-charge model (PCM) and first principles density functional theory (DFT).…”

Crystal field splitting in NdAl3 studied by inelastic neutron scattering

“…The CEF parameters R;L in (1) can be written [el as BY = A y ( r , ) Or where Fig. 9 this set of parameters describes very well the neutron scattering spectra given in [12]. The validity of this parameter scaling has been found already for the Laves phase of REAl,.…”

Implementation of cross correlation for energy discrimination on the time-of-flight spectrometer CORELLI

“…To demonstrate that the CORELLI instrument provides energy discrimination, we have measured the crystal electric field (CEF) excitation in PrAl 3 at 5 K using a powder sample, with the temperature regulated using a closed-cycle refrigerator. The first excited CEF level of Pr 3+ is well known to be located at 4 meV above the ground state (Goossens et al, 1996;Andreeff et al, 1978). Figs.…”