SKM 2023 – wissenschaftliches Programm

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TT: Fachverband Tiefe Temperaturen

TT 42: Poster: Correlated Electrons I

TT 42.3: Poster

Mittwoch, 29. März 2023, 15:00–18:00, P2/OG2

Searching for the critical endpoint in cobalt-doped EuRh₂Si₂ — •Franziska Walther, Alexej Kraiker, Kristin Kliemt, and Cornelius Krellner — Physikalisches Institut, Goethe-Universität Frankfurt, 60438 Frankfurt/Main, Germany

The ternary europium-based intermetallic compounds with the ThCr₂Si₂-type structure show a variety of intriguing physical properties due to the coupling between lattice and electronic degrees of freedom. Eu ions can be present in a magnetic divalent or non-magnetic trivalent state. Under variation of temperature and pressure, it’s possible to enforce a valence transition associated with a change of the unit cell volume [1]. At ambient pressure, EuRh₂Si₂ orders antiferromagnetically below T_N= 24 K in a stable divalent state [2], whereas the isoelectronic related compound EuCo₂Si₂ is nearly trivalent und indicates no magnetic ordering [1]. EuRh₂Si₂ undergoes a pressure-induced first order valence transition [3]. We expect the second order critical endpoint in the pressure range from 1.7 to 2.1 GPa, where the first-order phase transition terminates and critical elasticity may occur. We want to approach the critical endpoint by applying chemical pressure through substituting Rh in EuRh₂Si₂ with Co. We report on the growth of samples of the Eu(Rh_1−xCo_x)₂Si₂ -system and the characterization of their physical and chemical properties.
[1] Y. Onuki et al., J. Phys. Soc. Japan 89, 102001 (2020)
[2] S. Seiro, C. Geibel, J. Phys.: Condens. Matter 26, 046002, (2014)
[3] F. Honda et al., J. Phys. Soc. Japan 85, 063701 (2016)