SKM 2023 – wissenschaftliches Programm

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DS: Fachverband Dünne Schichten

DS 5: 2D Materials and their Heterostructures III

DS 5.4: Vortrag

Dienstag, 28. März 2023, 10:30–10:45, SCH A 316

Anisotropic Spontaneous Magnetostriction in Fe_3−xGeTe₂ — •Reinhard K. Kremer and Eva Brücher — MPI for Solid State Research, Stuttgart, Germany

By determining the lattice parameters as a function of temperature of the hexagonal van der Waals ferromagnet Fe_2.93(2)Ge_1.02(3)Te₂ we detect a spontaneous negative in-plane magnetostriction occuring below the Curie temperature. The spontaneous magnetostriction follows the square of the spontaneous magnetization and leads to an expansion of the hexagonal layers, and is clearly seen for the in-plane lattice parameter a, but less well pronounced perpendicular to the planes along c. Extrapolating to T →0 K we obtain a saturation spontaneous magnetostriction of λ_sp,a(T → 0) = -214(6) × 10⁻⁶ and a volume magnetotriction λ_sp,vol(T → 0) ≈ −450 × 10⁻⁶, indicating that the spontaneous magnetostriction along c is very small. The linear thermal expansion coefficients at 295 K of Fe_2.93(2)Ge_1.02(3)Te₂ amount to 13.9(1)×10⁻⁶ K⁻¹ and to 23.22(15)×10⁻⁶ K⁻¹ for the in-plane and out of plane direction, respectively, indicating in a linear volume thermal expansion coefficient of 51.0(2)×10⁻⁶.