SEMINARIUM INSTYTUTOWE

Dnia: 11.04.2018 roku (środa)
o godzinie 13:00 w auli

referat pt.:

Magnetyzm i nadprzewodnictwo w sieciach Kondo Ce-Pd-In

wygłosi

prof. dr hab. Dariusz Kaczorowski

Instytut Niskich Temperatur i Badań Strukturalnych PAN, Wrocław

The Ce–Pd–In system comprises several ternary phases crystallizing with different crystal structure types, including a few prototype ones. Some of these materials have been characterized for their physical properties and reported to exhibit a variety of nontrivial phenomena, which are predominantly governed by hybridization of cerium 4f-electronic states with conduction band states. The intensively studied compounds CePdIn and CePd₂In were found antiferromagnetic (AFM) Kondo lattices with heavy-fermion (HF) ground states, resulting from competing Kondo and RKKY interactions with similar energy scales. Dense Kondo effect, yet of considerably weaker magnitude, was evidenced also for AFM phases Ce₈Pd₂₄In, CePd₃In₂, CePd₂In₄, Ce₆Pd₁₂In₅ and non-stoichiometric Ce₂Pd₂In, as well as for ferromagnetic indide Ce₁₁Pd₄In₉. In contrast, hardly any hint at Kondo screening interactions was revealed for ferromagnetic CePdIn₂ and paramagnetic Ce₄Pd₁₀In₂₁. Most interestingly, the compound Ce₂PdIn₈ was discovered to exhibit unconventional HF superconductivity driven by magnetic fluctuations. In this material, the nodal superconductivity emerges in the proximity of AFM quantum critical point instability that manifests itself in the form of distinct non-Fermi liquid (NFL) features observed in the normal-state transport and thermodynamic properties. Similar NFL behavior was recently found in Ce₃PdIn₁1 and Ce₅Pd₂In₁₉, which form with crystal structures closely related to that of Ce₂PdIn₈, yet bearing multiple sites for Ce atoms in their crystallographic unit cells. Most remarkably, the former compound was established to exhibit at ambient pressure HF superconductivity that coexists with complex long-range AFM ordering. In our review of the physical properties of the Ce–Pd–In ternaries we shall supplement the literature data with our own hitherto unpublished results obtained on single crystals of a few selected materials.
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∗ This work was supported by the National Science Centre (Poland)
under research grant No. 2015/19/B/ST3/03158.