Dresden 2020 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 47: Poster Session Correlated Electrons 2
TT 47.8: Poster
Mittwoch, 18. März 2020, 15:00–19:00, P2/3OG
Magnetic phase diagram of Li2FeSiO4 — •Ahmed ElGhandour1, Martin Jonak1, Waldemar Hergett1, Sven Spachmann1, Mahmoud Abdel-Hafiez1,2, Johannes Werner1, Sven Sauerland1, Nadejda Bouldi3, Maurits Haverkort3, and Rüdiger Klingeler1 — 1Kirchhoff Institute of Physics, Heidelberg University, Germany — 2Faculty of Science, Physics Department, Fayoum University, Egypt — 3Institut für Theoretische Physik, Heidelberg University, Germany
Li2FeSiO4 single crystals of Pmnb-structure exhibit tetrahedrally coordinated Fe2+-ions in high-spin configuration and quasi-2D magnetic substructures. The anisotropy gap Δ = 2.9 meV implies significant anisotropy as compared to the antiferromagnetic dominant in-plane couplings along the crystallographic a- and c-directions, i.e., 1.0 and 3.6 meV, respectively. Notably, long-range AFM order evolving at TN=17 K is nearly completely suppressed by magnetic fields of 16 T. While, at higher magnetic fields additional phases appear which extend to 35 T and around 15 K. In addition to the unusual magnetic phase diagram, short-range correlations at least up to T ≈ 110 K are discussed with respect to short-range magnetic order and low-energy orbital excitations within the low-lying eg-orbitals.