Berlin 2018 – scientific programme

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TT: Fachverband Tiefe Temperaturen

TT 5: f-Electron Systems and Heavy Fermions I

TT 5.12: Talk

Monday, March 12, 2018, 12:45–13:00, H 3005

Crystalline electric field calculations for CeIr₃Ge₇ — •Jacintha Banda¹, Binod Rai², Emilia Morosan², Christoph Geibel¹, and Manuel Brando¹ — ¹Max Planck Institute for Chemical Physics of Solids, Nöthnitzer Str. 40, 01187 Dresden, Germany — ²Department of Physics and Astronomy, Rice University, Houston, Texas 77005, USA

CeIr₃Ge₇ is a metallic antiferromagnet with an extremely low Néel temperature of 0.65 K despite the absence of Kondo effect and geometrical frustration. We have solved the crystalline electric field (CEF) scheme for the well localized Ce³⁺ moment which has a trigonal point symmetry. We compared our calculations with experimental data on single crystalline samples and found an excellent agreement with one possible solution. This yields a large positive B₂⁰ CEF parameter, resulting in a large CEF splitting with the first and second excited CEF levels at 374 and 1398 K respectively. A large off diagonal B₄³ parameter leads to a strong mixing of the |±5/2> function into the predominantly |±1/2> CEF ground state. As a result, the system shows a huge XY anisotropy. The overall CEF splitting in this compound is one of the largest ever observed in a Ce system. Comparison with other compounds suggest that such large CEF splitting might be connected with the presence of 5d ligands.