Berlin 2018 – wissenschaftliches Programm

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TT: Fachverband Tiefe Temperaturen

TT 47: Frustrated Magnets - Iridates and Fe-based Materials

TT 47.10: Vortrag

Mittwoch, 14. März 2018, 12:00–12:15, H 0104

The magnetic phase diagram and short-range magnetic order in γ-Li₂FeSiO₄ — •Martin Jonak¹, Fabian Billert¹, Sisi Gu^1,2, Christoph Neef¹, Waldemar Hergett¹, Johannes Werner¹, Changhyun Koo¹, and Rüdiger Klingeler¹ — ¹Kirchhoff Institute for Physics, University of Heidelberg, Heidelberg, Germany — ²University of Science and Technology of China, Hefei, China

We report thermal expansion, specific heat, and high-frequency electron spin resonance (HF-ESR) studies up to 17 T, as well as pulsed-field magnetisation data on a γ-Li₂FeSiO₄ (space group Pmnb) single crystal. The data imply the onset of long-range antiferromagnetic order at T_N=17.0(5) K. The uniaxial pressure dependencies are derived from our uniaxial thermal expansion data. At low temperatures, the saturation field for B||easy axis amounts to 33 T. In addition, there are several field-induced anomalies suggesting competing magnetic phases. The antiferromagnetic resonance modes exhibit significant zero-field splitting associated with magnetic anisotropy. At higher temperatures, the HF-ESR data imply the evolution of local magnetic fields at least up to 100 K, and are accompanied by sizeable magnetostriction well above T_N.