Berlin 2024 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 80: Correlated Electrons: Poster
TT 80.7: Poster
Donnerstag, 21. März 2024, 15:00–18:00, Poster E
Effect of substitutions and disorder on the valence transition in YbIn1−x(Ag/Au)xCu4 single crystals — •Michelle Ocker, Bereket Ghebretinsae, Jan Niklas Zimmermann, Bernd Wolf, Kristin Kliemt, Michael Lang, and Cornelius Krellner — Physikalisches Institut, Goethe Universität Frankfurt, 60438 Frankfurt/Main, German
YbInCu4 is one of the rare cases which exhibits a 1st-order valence
transition at ambient pressure as a function of temperature around
Tv = 42 K [1]. The first-order valence transition line is terminated at
a second-order critical endpoint (CEP) [2] where strong fluctuations
together with strong coupling effects can be expected. In order to identify these effects and to study them in more detail, single crystalline
samples were prepared in In-Cu flux [3]. To tune the material to a point
close to the CEP in the valence cross-over region single crystals substituted with silver and gold were prepared. To fine-tune the substituted
samples measurements under He-gas pressure were performed. We report on the single crystal growth with different substitution levels
and different initial compositions. We present the results of our structural, chemical and physical characterization for the various samples.
We show the elastic constant cL(T,p) and discuss the behaviour of the
magneto-elastic coupling constant near the CEP.
[1] I. Felner et al., Physical Review B 35, (1987) 6956.
[2] Y. Onuki et al., J. Phys. Soc. Japan 89, (2020) 102001.
[3] J. L. Sarrao et al., Physical Review B 54, (1996) 12207.
Keywords: phase transition; valence cross-over; critical endpoint; crystal growth