Einkristallzüchtung von Cer-Verbindungen ohne Inversionssymmetrie
Zusammenfassung der Projektergebnisse
Non-centrosymmetric Ce compounds attract great interest for various reasons. The lack of inversion symmetry permits coupling terms between different degrees of freedom that shed new light on the interplay of multiple, nearly degenerate energy scales for strong electronic correlations. This raises in particular the possibility of strong hybridisation between electronic and lattice degrees of freedom. The lack of inversion symmetry allows also for effects of strong spin-orbit coupling in the electronic structure and magnetic order, where they might drive unconventional topologies. Moreover, selected members of this class of materials display heavy fermion superconductivity that is putatively outside the traditional classification schemes. The project pursued the implementation of crystal growth apparatus for the preparation of high purity single crystals of selected non-centrosymmetric Ce compounds by means of radio-frequency induction heating and optical float-zoning. As part of a UHV-compatible preparation chain a bespoke casting furnace was developed. Growth of several different materials systems was attempted. Large single crystals of the series of CeTAl3 (T=Au, Ag, Cu, Pd, Pt) were grown. The crystal structure of these compounds was determined by means of x-ray diffraction and neutron scattering. The low temperature transport and bulk properties were measured comprehensively. The magnetic properties appear to be related in a systematic manner across the series in terms of the c/a ratio of the lattice constants. An extensive inelastic neutron scattering study was carried out in CeAuAl3, where the signatures of strongly hybridized magnetoelastic excitations were observed. Preliminary high-pressure experiments were carried out on several members of this series of compounds. The experimental studies on the Ce compounds were complemented by work on non-centrosymmetric transition metal compounds in order to guide the search for topologically non-trivial spin textures. On the technological side the crystal growth apparatus offers significant improvements. As the main scientific result this project identifies the class of CeTAl3 compounds and isostructural siblings as being ideally suited for detailed studies of the nature of electronic correlations in Ce-based materials with multiple, nearly degenerate energy scales.
Projektbezogene Publikationen (Auswahl)
- Distribution of lattice constants in CePt3Si observed by Larmor diffraction and SANS. J. Phys.: Conf. Series 200, 012165 (2010)
R. Ritz, S. Mühlbauer, C. Pfleiderer, T. Keller, J. White, M. Laver, E. M. Forgan, R. Cubitt, C. Dewhurst, P. G. Niklowitz, A. Prokofiev, E. Bauer
- Skyrmion lattices in metallic and superconducting B20 transition metal compounds. J. Phys. Cond. Matter 22, 164207 (2010)
C. Pfleiderer, T. Adams, A. Bauer, W. Biberacher, B. Binz, F. Birkelbach, P. Böni, C. Franz, R. Georgii, M. Janoschek, F. Jonietz, R. Ritz, S. Mühlbauer, W. Münzer, A. Neubauer, B. Pedersen, A. Rosch
- Ultrahigh-Vacuum compatible image furnace. Rev. Sci. Instrum. 82, 013902 (2011)
A. Neubauer, J. Boeuf, A. Bauer, B. Russ, H. v. Löhneysen, C. Pfleiderer
- A Raman study of the temperature and magnetic field dependence of electronic and lattice properties in MnSi. Phys. Rev. B 90, 024411 (2014)
H.-M. Eiter, P. Jaschke, R. Hackl, A. Bauer, M. Gangl, C. Pfleiderer
(Siehe online unter https://doi.org/10.1103/PhysRevB.90.024411) - Single crystal growth of CeTAl3 (T=Cu, Ag, Au, Pd and Pt)
C. Franz, A. Senyshyn, A. Regnat, C. Duvinage, R. Schönmann, A. Bauer, Y. Prods, L. Akselrud, V. Hlukhyy, V. Baran, C. Pfleiderer
- Ultra-high vacuum compatible induction-heated rod casting furnace. Review of Scientific Instruments 87, 063909 (2016)
A. Bauer, A. Neubauer, W. Münzer, A. Regnat, G. Benka, M. Meven, B. Pedersen, C. Pfleiderer
(Siehe online unter https://doi.org/10.1063/1.4954926)
