Wydarzenie w dniu 11.04.2018:
Dnia: 11.04.2018 roku (środa)
o godzinie 13:00 w auli
Magnetyzm i nadprzewodnictwo w sieciach Kondo Ce-Pd-In
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of the physical properties of the Ce–Pd–In ternaries we shall supplement the literature data with our own hitherto unpublished results obtained on single crystals of a few selected materials.
∗ This work was supported by the National Science Centre (Poland)
under research grant No. 2015/19/B/ST3/03158.