SKM 2023 – wissenschaftliches Programm

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MA: Fachverband Magnetismus

MA 23: Poster Magnetism I

MA 23.25: Poster

Dienstag, 28. März 2023, 17:00–19:00, P1

Origin of Ferromagnetism in the Copper(II) Triangle NMe₄[Cu₃(µ₃-F)(TFA)₆(Py)₃] — •Kevin Ackermann^1,2, Changhyun Koo¹, Ahmed Elghandour¹, Rüdiger Klingeler¹, and Maurits W. Haverkort² — ¹1Kirchhoff Institute for Physics, Heidelberg, Germany — ²for Theoretical Physics, Heidelberg, Germany

The new copper(II) triangle NMe₄[Cu₃(µ₃-F)(TFA)₆(Py)₃] [1] was studied using magnetic susceptibility and high-field electron paramagnetic resonance (HF-EPR) experiments, as well as numerically by ab-initio methods. The magnetization and susceptibility data reveal dominant ferromagnetic spin-spin exchange as well as the importance of anisotropy in the system. An Anderson Impurity Model based on LDA-DFT calculations elucidates that the ferromagnetic interactions originate from super-exchange via the central fluorine. For the super-exchange interaction, not only the fluorine’s 2p shell but also the 2s shell needs to be considered. In the HF-EPR date a substantial curvature of the resonance branches is observed and explained within the model by mixing between exited S_z≈1/2 and S_z≈−1/2 states. The model also suggests that the spins are not parallel to each other in the ferromagnetic ground state but rather arranged in a chiral manner which is given by the molecular structure.

[1] A. Vassiliev et al., unpublished.