Neutron spectroscopic study of crystal-field excitations and the effect of the crystal field on dipolar magnetism inLiRF4(R=Gd, Ho, Er, Tm, and Yb)

Abstract

We present a systematic study of the crystal-field interactions in the LiRF 4 (R = Gd, Ho, Er, Tm, and Yb) family of rare-earth magnets. Using detailed inelastic neutron scattering measurements, we have been able to quantify the transition energies and wave functions for each system. This allows us to quantitatively describe the high-temperature susceptibility measurements for the series of materials and make predictions based on a mean-field approach for the low-temperature thermal and quantum phase transitions. We show that coupling between crystal field and phonon states leads to line-shape broadening in LiTmF 4 and level splitting in LiYbF 4 . Furthermore, using high-resolution neutron scattering from LiHoF 4 , we find anomalous broadening of crystal-field excitations which we attribute to magnetoelastic coupling.

Crystal electric field in CeRh2Si2 studied with high-resolution resonant inelastic soft x-ray scattering

“…Temperature dependent measurements can also be useful in inelastic neutron scattering experiments, where thermal population of excited states can, for instance, help detecting CEF excitations that are forbidden at zero temperature due to selection rules (see, e.g., Refs. [26] and [27] for recent examples). At zero temperature the energy of excited CEF levels is simply given by the position of the peaks in the energy loss spectra.…”

Single-ion properties of theSeff=12XY antiferromagnetic pyrochloresNaA′Co2Ross1, Brown2, Cava3 et al. 2017Phys. Rev. B505561View full textAdd to dashboardCite

“…This method was used to fit the data presented in Section IV B. The method is similar to that used for the rare earth based magnets, 42,43 and results in similar phenomenology. The single ion levels for Co 2+ in a trigonally distorted octahedron are Kramers doublets with anisotropic moments described by a g-tensor.…”

Probing strongly hybridized nuclear-electronic states in a model quantum ferromagnet

“…We successfully trace the temperature and field evolution of the spectrum over the entire phase diagram, and show that it is remarkably well reproduced by a mean-field calculation with parameters set by independent spectroscopic measurements [3,4,7,8].…”

“…1) [2]; and (ii) incomplete mode softening of the low-energy electronic excitations at the critical point [6]. Therefore, this system provides a rare opportunity to explore the quantum phase transition of a magnet coupled to a nuclear spin bath [2,[6][7][8].The impact of strong hybridization has also been highlighted for magnetic-ion diluted insulators, such as LiYF 4 :Ho 3+ , using magnetic resonance [9,10]. A similar line of effort has achieved more recently single-molecule magnetic resonance with a rare-earth ion [11].…”

“…1) [2]; and (ii) incomplete mode softening of the low-energy electronic excitations at the critical point [6]. Therefore, this system provides a rare opportunity to explore the quantum phase transition of a magnet coupled to a nuclear spin bath [2,[6][7][8].…”