Benchmarking Cantilever Torque Magnetometry as a Platform for Characterizing Molecular Qubits: A Case Study on Ni(II) Complexes
Year: 2026
Authors: Janetzki J.T., Raza A., Briganti M., Duquennoy R., Barra AL., Toninelli C., Perfetti M., Sorace L.
Autors Affiliation: Univ Florence, Dept Chem Ugo Schiff, I-50019 Sesto Fiorentino, Italy; Univ Florence, INSTM Res Unit, I-50019 Sesto Fiorentino, Italy; European Lab Nonlinear Spect LENS, I-50019 Sesto Fiorentino, Italy; Natl Inst Opt CNR INO, I-50019 Sesto Fiorentino, Italy; Univ Grenoble Alpes, Lab Natl Champs Magnet Intenses, CNRS, F-38042 Grenoble, France.
Abstract: Precise and experimentally accessible determination of the electronic structure of transition metal complexes remains a challenge in the development of molecular qubits, particularly for leading candidates with integer spin. Existing techniques often require large-scale facilities and substantial sample quantities or offer limited spectral access and sensitivity to subtle anisotropies. Here, we demonstrate that cantilever torque magnetometry (CTM) overcomes these limitations by combining high sensitivity to magnetic anisotropy with wide sample compatibility, minimal sample demands, and true laboratory-scale accessibility. By exploiting the distinct temperature dependences of g-tensor anisotropy and zero-field splitting (ZFS), CTM enables their experimental decoupling, yielding exceptionally precise bulk-mean value determination of spin Hamiltonian parameters from microgram-scale single crystals. The parameters extracted by CTM were found to be qualitatively consistent but quantitatively different from those determined using high-frequency electron paramagnetic resonance spectroscopy (similar to 1% for g and similar to 5-15% for ZFS), highlighting that perfect agreement between magnetometric and resonance techniques is not guaranteed. Our study establishes CTM as a powerful and broadly accessible complement to magnetic resonance methods, opening new routes for high-precision characterization of low-anisotropy spin systems in molecular quantum information science.
Journal/Review: JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
Volume: 148 (10) Pages from: 11260 to: 11273
More Information: This work has been funded by the European Union (ERC, QUINTESSEnCE, 101088394). Views and opinions expressed are, however, those of the author(s) only and do not necessarily reflect those of the European Union or the European Research Coun cil. Neither the European Union nor the granting authority can be held responsible for them. L. S. also acknowledges the financial support of PNRR-MUR Project No. PE0000023-NQSTI. We thank Prof. Colette Boskovic for synthetic support and Dr Leonardo Passerini for assistance in the collection of W-band EPR spectra.KeyWords: Electron-paramagnetic-resonance; Transition-metal-complexes; Zero-field Splittings; Magnetic-anisotropy; High-frequency; Ni-ii; Magnetostructural Correlations; Dinuclear Complexes; Solid-state; SpinDOI: 10.1021/jacs.6c00500
