TY  - JOUR
PB  - SciPost Foundation
DO  - 10.21468/SciPostPhysProc.11.022
TI  - From magnetic order to valence-change crossover in EuPd$_2$(Si$_{1-x}$Ge$_x$)$_2$ using He-gas pressure
PY  - 2023/06/19
UR  - https://scipost.org/SciPostPhysProc.11.022
JF  - SciPost Physics Proceedings
JA  - SciPost Phys. Proc.
VL  - 
IS  - 11
SP  - 022
A1  - Wolf, Bernd
AU  - Spathelf, Felix
AU  - Zimmermann, Jan
AU  - Lundbeck, Theresa
AU  - Peters, Marius
AU  - Kliemt, Kristin
AU  - Krellner, Cornelius
AU  - Lang, Michael
AB  - We present results of magnetic susceptibility and thermal expansion measurements performed on high-quality single crystals of EuPd$_2$(Si$_{1-x}$Ge$_x$)$_2$ for 0 $\leq x \leq$ 0.2 and temperatures 2 K $\leq T \leq$ 300 K. Data were taken at ambient pressure and finite He-gas pressure $p$ $\leq$ 0.5 GPa. For $x = 0$ and ambient pressure we observe a pronounced valence-change crossover centred around $T'_V$ $\approx$ 160 K with a non-magnetic ground state. This valence-change crossover is characterized by an extraordinarily strong pressure dependence of d$T'_V$ /d$p$ = (80 $\pm 10)$ K/GPa. We observe a shift of $T'_V$ to lower temperatures with increasing Ge-concentration, reaching $T'_V$ $\approx$ 90 K for $x = 0.1$, while still showing a non-magnetic ground state. Remarkably, on further increasing $x$ to 0.2 we find a stable Eu$^{(2+\delta)+}$ valence with long-range antiferromagnetic order below $T_N$ = (47.5 $\pm$ 0.1) K, reflecting a close competition between two energy scales in this system. In fact, by the application of hydrostatic pressure as small as 0.1 GPa, the ground state of this system can be changed from long-range antiferromagnetic order for $p$ $<$ 0.1 GPa to an intermediate-valence state for $p$ $\geq$ 0.1 GPa.
ER  -

@Article{10.21468/SciPostPhysProc.11.022,
	title={{From magnetic order to valence-change crossover in EuPd$_2$(Si$_{1-x}$Ge$_x$)$_2$ using He-gas pressure}},
	author={Bernd  Wolf and  Felix  Spathelf and  Jan  Zimmermann and Theresa  Lundbeck and Marius  Peters and Kristin  Kliemt and Cornelius  Krellner and  Michael  Lang},
	journal={SciPost Phys. Proc.},
	pages={022},
	year={2023},
	publisher={SciPost},
	doi={10.21468/SciPostPhysProc.11.022},
	url={https://scipost.org/10.21468/SciPostPhysProc.11.022},
}