Pressure-induced valence change of YbNiGe3investigated by resonant x-ray emission spectroscopy at the YbL3edge

Abstract

Pressure dependence of the Yb valence in YbNiGe 3 has been investigated up to 15.6 GPa at 300 K and up to 7.7 GPa at 17 K by means of x-ray absorption spectroscopy in Lα 1 partial fluorescence yield mode and resonant x-ray emission spectroscopy around the Yb L 3 absorption edge. The Yb valence in YbNiGe 3 at ambient pressure strongly fluctuates with the mean valence of v = 2.52 ± 0.01 at 300 K. The Yb valence rapidly changes toward a trivalent state with pressure up to ∼5 GPa, slowly increases up to ∼10 GPa, and then reaches a saturated value of v ∼ 2.87 at 15.6 GPa. The Yb valence at 17 K slightly decreases compared to that at 300 K; v ∼ 2.45 at ambient pressure and ∼2.72 at 7.7 GPa. We found that the pressure-induced change in the intensity of a quadrupole component in the x-ray absorption spectra shows the same trend as the Yb valence in YbNiGe 3. In contrast to YbNiGe 3 , the Yb valence in YbNiSi 3 is nearly 3 at ambient pressure with almost no temperature dependence.

Tuning the electronic hybridization in the heavy fermion cage compound YbFe2Zn20with Cd doping

“…DC magnetic susceptibility measurements (Fig. 4) show a broad maximum that is typical of valence fluctuating systems, but can also be related to the Kondo physics [26] [31,33]). The crossover region between these two regimes does not have a well-defined limit, so shifts in the maximum of the magnetic susceptibility for such crossover systems can be indicative of shifts in both the Kondo-type interaction (T K ) and the spin-fluctuation (T sf ).…”

Pressure-induced anomalous valence crossover in cubic YbCu5-based compounds

“…24 ) and YbNiGe 3 (ref. 25 ), the Yb valence increases with pressure and shows a pronounced change in the slope around the QCP. Our results in YbCu 5 show that the valence stabilizes around 5 GPa and decreases slightly at 5–15 GPa.…”

Concomitant singularities of Yb-valence and magnetism at a critical lattice parameter of icosahedral quasicrystals and approximants

“…2 b), respectively. Using the intensities of the resonant components of the and configurations, and , we define an Yb mean-valence as follows 27 , Rose-pink line in the figure indicates summation of the resonant and fluorescence components fitted to the data.…”

“…The spectrum consists of two components, a resonant component yielding the double-peaked structure, and a double-step-like fluorescence component contributing to the background spectrum, as observed in other IV compounds 27,28 . The resonant and fluorescence components were assumed to be described by a Discovery of new IV QCs/ACs.…”