Berlin 2012 – scientific programme

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TT: Fachverband Tiefe Temperaturen

TT 3: Correlated Electrons: Heavy Fermions

TT 3.6: Talk

Monday, March 26, 2012, 10:45–11:00, H 3005

Superconductivity in an intermediate valence Ce compound with a quasi-two-dimensional structure — •Thomas Gruner¹, Miss. Anupam², Zakir Hossain², and Christoph Geibel¹ — ¹MPI for Chemical Physics of Solids, 01187, Dresden, Germany — ²Department of Physics, IIT Kanpur, 208016, Kanpur, India

Binary rare earth - transition metal metallographic phase diagrams show a large immiscibility gap for early transition metals (i.e. from the left side of the periodic table). As a result, no binary compound forms and only very few ternary compounds have been reported. Among them CeRe₄Si₂ presents an interesting structure: a stacking of Re₂Si and Ce layers results in a quasi-two-dimensional character. The preparation of this compound is challenging because of the high melting point of Re (3180 ^∘C) and the fact that CeRe₄Si₂ likely forms in a solid-state reaction. We developed an appropriate synthesis process and obtained almost phase pure polycrystalline samples. Results of electrical resistivity, magnetic susceptibility and specific heat measurements show that Ce is in an intermediate valence state and that the compound becomes superconducting below T_c ≈ 3.2 K. CeRe₄Si₂ is thus one of the very few intermediate valence Ce-based superconductors. The properties of this superconducting state will be discussed.