Observation of intermultiplet transitions in rare-earth metal ions by inelastic neutron scattering

Samarium: magnetic neutron spectroscopic intensities

“…A vertical line at ( = 146 meV indicates the spin-orbit strength listed by Carnall et al [5]. We note, however, that the neutron measurements of Williams et al and Needham et al [1,3] put the first excited level 6 H 7 ; 2 at 130 meV above the ground state, which corresponds to a spin-orbit strength ( ~ 160 me V in Fig. 1.…”

“…Kl41t rA• 1 J Figure 4: A calculated neutron spectrum resulting from neutrons with a sample incident energy of 2500 meV. The peak at 130 meV has been observed by Williams et al [1]. The additional spectral features around 800 meV arise from inter-term (Coulomb) transitions induced by magnetic neutron scattering.…”

“…Energy level schemes for several rare earth and actinide atoms have been established with good accuracy. In the seminal experiment Williams et al [1] investigated Samarium• in its trivalent state and measured the wave vector dependence of the first inelastic transition at 130 me V from the ground state 6 H 5 ; 2 to 6 H 7 ; 2 . Even with the high intensity of a pulsed spallation source the experiment proved to be very difficult due to the strong neutron absorption encountered in natural Samarium.…”

FIRST ORDER MAGNETIZATION PROCESS IN Sm (Fe11Ti)

“…We have established an exchange and crystal-field model t o account for available experimental data on the R (FellTi) series. The first excited multiplet 6~~1 2 of the sm3+ ion is only 1438 K [7] above the ground state 6~s12. It is therefore necessary to take account of J-mixing as in the case of SmM5 (M = Co [8,91,Ni [lo]).…”

“…It is therefore necessary to take account of J-mixing as in the case of SmM5 (M = Co [8,91,Ni [lo]). The total Hamiltonian for the sm3+ ion can be written as The first term above is due to spin-orbit coupling with X = 411.1 K [7]; the second term represents the exchange interaction between Sm and Fe sublattices, with an exchange coefficient ns,F, deduced from the Curie temperature [ll] of 300 po; the third term is the crystal-field Hamiltonian for the 2a site in the tetrago- field. Our method of calculation is the same as that used for NdzFelrB [14].…”