Dresden 2026 – scientific programme

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MA: Fachverband Magnetismus

MA 42: Molecular Magnetism and Magnetic Particles / Clusters II

MA 42.6: Talk

Thursday, March 12, 2026, 10:45–11:00, HSZ/0004

Exchange-biased toroidal moments in a family of homochiral Cu₆Ln₃ complexes studied by high-field EPR — •Jan Arneth¹, Deepanshu Chauhan², Sagar Paul³, Bapan Jana², Wolfgang Wernsdorfer³, Maheswaran Shanmugam², Gopalan Rajaraman², and Rüdiger Klingeler¹ — ¹Kirchhoff Institute for Physics, Heidelberg University, Germany — ²Department of Chemistry, Indian Institute of Technology Bombay, India — ³Physikalisches Institut, Karlsruhe Institute of Technology, Germany

The vortex-like arrangement of the individual magnetic moments renders single-molecule toroics (SMT) promising candidates for application in quantum computing, molecular spintronics and the development of magneto-electric coupling in multiferroic devices. Here, we report the magnetic investigation of a family of heterobimetallic nonanuclear Cu₆Ln₃ (Ln = Y,Gd,Dy) clusters, featuring a homochiral Cu₃-Ln₃-Cu₃ triangular core, using combined theoretical ab-initio, ac and dc susceptibility, µ-SQUID and high-field EPR studies. Numerical analysis of our experimental data allow for the determination of the microscopic spin Hamiltonian parameters, which reveal an antiferromagnetic inter-triangular coupling between the two spin-frustrated Cu₃ units. In particular, Cu₆Dy₃ exhibits both single-molecule magnet (SMM) and SMT behaviour with a non-magnetic ground state persisting up to magnetic fields as high as B ≃ 1.3 T. The large excitation gap is found to result from the ferromagnetic Cu-Dy exchange interaction coupling the toroidal Dy₃ unit with the adjacent Cu₃ triangles.

Keywords: High-Field Electron Paramagnetic Resonance; Single-molecule Magnets; Single-molecule Toroics; Magnetic 3d-4f Coupling; Spin Frustration