Crystal Electric Field Splitting Research Articles

Extraordinary temperature shifts and site-dependent linewidths of the Eu 3+5D 0→ 7F 1 emission lines of Eu 0.36Tb 0.64P 5O 14

A reduction of the crystal electric field (CEF) splitting of the 7F 1 multiplet of Eu 3+ with decreasing temperature is observed. This extraordinary phenomenon is similar to the analogous pressure-induced reduction of the CEF splitting of this multiplet. It is unlikely that the temperature effect is due to a temperature-induced approach toward high symmetry because a temperature decrease is known to lower the site symmetry. Resonant electron-phonon interactions between the 7F 1 states and optical phonons with similar energies which result in a repulsion of the lowest 7F 1 state toward higher energy may be the origin of the pressure and temperature effects. A plot of the time-resolved fluorescence line-narrowing linewidths of the 5D 0→ 7F 1(ϵ 0) transition vs. excitation energy have a minimum at the absorption peak value. This minimum can be explained either by an accidental coincidence in the excitation energy of ions at different sites or by different rates of excitation transfer to acceptors when the donors are excited via the center or via the wings of the absorption profile.

Determination of deuterium localization in PrNi 5D 0.44 by crystal electric field effects

The high local sensitivity of the crystal electric field (CEF) was used to determine the site where deuterium localizes in the solid solution phase PrNi 5D 0.44. This compound is a structural analogue of the well-known hydrogen storage intermetallic compound LaNi 5. The influence of deuterium dissolved in PrNi 5 on the CEF splitting of the Pr 3+ ground multiplet was investigated using the inelastic neutron scattering technique. A new method of describing the CEF in metals was developed to interpret the experimental data. This method is more physically meaningful than the effective point charge model. The experimental data obtained (a decrease of about 40% in the intensity of the main peak in the PrNi 5D 0.44 spectrum compared with the PrNi 5 spectrum and the appearance of an extra scattering peak in some spectral regions) and the results of the Pr 3+ ground state splitting calculations for the deuterated sample suggest that deuterium is located in the vicinity of the m site in PrNi 5D 0.44. The effective electrostatic potential of deuterium in PrNi 5 decreases less abruptly than the potential of the free deuterium (hydrogen) atom.

Theory of magnetic susceptibility of mixed-valent Ce0.76La0.14Th0.1

The authors derive an expression for the magnetic susceptibility ( chi ) of a mixed-valent system in which there is a continuous valence transition to a nearly integral valent phase, taking into account the crystal electric field (CEF) splitting of the localised levels. As an example, they calculate chi of Ce0.76La0.14Th0.1 in which CEF excitations have been observed for the first time in a mixed-valent system. There is a good agreement with experimental results.

Magnetic interactions of Ho 3+ in HoCrO 3 — A neutron diffraction study

The temperature dependence of the intensity of a purely Ho 3+ magnetic Bragg reflection from a HoCrO 3 powder sample was measured. The antiferromagnetic component of the Ho 3+ sublattice magnetization, μ Ho y ( T), was derived. An analysis of μ Ho y ( T) together with the previously measured spontaneous magnetization of the HoCrO 3 is performed. The analysis confirms that the canting angles of the Cr and Ho sublattices are constant, and is consistent with the values obtained for these angles. The Ho-Cr and Ho-Ho interactions, the g factor of the “accidental” doublet and its crystal electric field splitting were derived by a molecular field analysis of the data. The Ho-Ho interaction was found to be of opposite sign and much smaller than the Ho-Cr interaction. The values of the parameters are in agreement with those found by other techniques.

The specific heat jump of superconducting La 1- xTb xAl 2 related to crystal electric field splitting of the Tb 3+ levels

Measurements of the specific heat jump Δ c(Tinc) were performed on superconducting La 1- x Tb x Al 2 compounds in order to investigate the pairbreaking effect of Tb 3+ ions in the LaAl 2 host. The results deviate from the Abrikosov-Gorkov theory for superconductors with magnetic impurities. Taking into account the crystal field level structure of Tb 3+ in LaAl 2 the results can be qualitatively understood within the model of Fulde, Keller and Peschel. According to calculations published by Müller-Hartmann and Zittartz an influence of the Kondo effect can be ruled out.