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TT: Fachverband Tiefe Temperaturen
TT 17: Poster Session: Correlated Electrons 1
TT 17.36: Poster
Montag, 1. April 2019, 15:00–18:30, Poster D
Static magnetic order in γ-Li2FeSiO4 as probed by 57Fe Mössbauer spectroscopy — •Felix Seewald1, Sascha Albert Bräuninger1, Rüdiger Klingeler2, Waldemar Hergett2, and Hans-Henning Klauss1 — 1Institute of Solid State and Materials Physics, TU Dresden, D-01069 Dresden, Germany — 2Kirchhoff Institute of Physics, Heidelberg University, D-69120 Heidelberg, Germany
γ-Li2FeSiO4 is proposed as a promising candidate material for lithium ion batteries. The Fe atoms are tetrahedrally coordinated by Oxygen. Iron has the Fe2+ (S=2) oxidation state and is displaced from the tetrahedron center resulting in a electric field gradient caused by the distorted tetrahedral crystal field. The Mössbauer spectrum of the powder sample shows one dominant site exhibiting magnetic order at 2.1 K and a considerable quadrupole splitting as observed at room temperature. The magnetic hyperfine field of B = 14.7(4) T is oriented orthogonal to the largest principle axis of the electrical field gradient Vzz = −125(3) V/Å2. The isomer shift of δ = 1.1(1) mm/s is consistent with the high spin Fe2+ (S=2) state. We will discuss the implications of these findings on the actual magnetic structure in this system. The observed static order is in agreement with susceptibility measurements showing a transition to antiferromagnetic order below 17 K.