Regensburg 2016 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 43: Correlated Electrons: f-Electron & Heavy Fermion Systems
TT 43.11: Hauptvortrag
Mittwoch, 9. März 2016, 12:15–12:45, H20
Rare-earth-like behavior of transition metals substituted in Li3N — •Anton Jesche — EP 6, Electronic Correlations and Magnetism, University of Augsburg, Germany
Large magnetic anisotropy and coercivity are key properties of functional magnetic materials and are generally associated with rare-earth elements. The magnetic anisotropy of 3d transition metals, on the other hand, is usually considered to be weak. Main reason is the widely known paradigm of orbital quenching. However, a rare interplay of crystal electric field effects and spin-orbit coupling causes a large orbital contribution to the magnetic moment of the T = {Mn, Fe, Co and Ni} in Li2(Li1−xTx)N. Accordingly, extremely large magnetic anisotropies have been found. Most notably, the magnetic anisotropy alternates as easy plane → easy axis → easy plane → easy axis when progressing from T = Mn → Fe → Co → Ni [1].
Furthermore, experimental evidence for a macroscopic quantum tunneling of the magnetization has been observed in diluted Li2(Li1−xFex)N with x ≪ 1. Steps in the hysteresis loops and relaxation phenomena in striking similarity to single-molecule magnets indicate the presence of nanoscale magnetic centers, which are likely built from single, isolated iron atoms [2].
Recent results are going to be discussed and contrasted with established molecular magnets, hard permanent magnets and rare-earth-based model systems.
A. Jesche et al. Phys. Rev. B 91, 180403(R) (2015)
A. Jesche et al., Nature Comm. 5:3333
doi: 10.1038/ncomms4333 (2014)