2024/01/25 by Reinhard K. Kremer, Kremer, R. K., E. Bruecher +1 · 1 citation
Materials Science · #2D Materials and Applications #FOS: Physical sciences #Graphene research and applications #Iron-based superconductors research #Strongly Correlated Electrons (cond-mat.str-el)
paper · pdf · doi:10.48550/arxiv.2401.14050
openalex publication_date 2024/01/25 · openalex created_date 2024/01/27 · openalex updated_date 2026/07/28
By determining the lattice parameters as a function of temperature of the hexagonal van der Waals ferromagnet Fe2.92(1)Ge1.02(3)Te2 we obtain the temperature dependence of the spontaneous in-plane magnetostriction in the ferromagnetic and the linear thermal expansion coefficients in the paramagnetic state. The spontaneous magnetostriction is clearly seen in the temperature dependence of the in-plane lattice parameter a(T), but less well pronounced perpendicular to the planes along c. Below T\rm C the spontaneous magnetostriction follows the square of the magnetization and leads to an expansion of the hexagonal layers. Extrapolating to T→ 0~K we obtain a spontaneous in-plane saturation magnetostriction of λ_\rm sp,a(T → 0) ≈-220 ~×~10-6. In the paramagnetic state the linear thermal expansion coefficients amount to 13.9(1)×10-6~K-1 and to 23.2(2)×10-6~K-1 for the in-plane and out-of-plane direction, respectively, indicating a linear volume thermal expansion coefficient of 50.8(4)×10-6K-1 which we use to estimate the volume thermal expansion contribution to the heat capacity determined at constant pressure. A Sommerfeld-type linear term in the low-temperature heat capacities can be quantitatively ascribed to 2dim ferromagnetic magnon excitations.