Molecular magnetism and molecular spintronics

Modelling of molecular magnets

Molecular magnets are large molecules containing magnetic centers in the form of transition or lanthanides metal ions. Due to magnetic shielding by ligands the interaction between magnetic ions is not negligible only within a molecule. Nanoscopic size of these molecules induces their peculiar magnetic properties, which reflect quantum nature of a spin in measurements carried out for bulk samples. Thus, they can be used as a testbed for various quantum theories. Precise modeling of such systems is crucial both for understanding their quantum nature and in view of envisaged applications: in quantum information processing, molecular electronics, magnetic refrigeration, or other. We model various molecular magnets such as e.g. spherical mixed-valent polyoxovanadates, chromium based rings,  or single ion magnets based on lanthanide ions with strong spin orbit interaction.

Our research:

  • Study of the relation between quantum entanglement and magnetic frustration in chromium based molecular rings [1]
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  • Elucidation of electronic and magnetic properties of mixed-valence polyoxovanadates with different combinations of itinerant and localized valence electrons induced by various quest molecules. [2,3,4,5]
molecular magnets
  • Modeling of hybrid molecular magnets based on polyoxometalates connected to lanthanide ions with phthalocyanine ligand. [6,7]
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  1. P. Kozłowski, Frustration and quantum entanglement in odd-membered ring-shaped chromium nanomagnets, Phys. Rev. B 91, 174432 (2015)
  2. K. Yu. Monakhov, O. Linnenberg, P. Kozłowski, J. van Leusen, C. Besson, T. Secker, A. Ellern, X. López, J. M. Poblet, and P. Kögerler, Supramolecular Recognition Influences Magnetism in [X@HVIV8VV14O54]6- Self-Assemblies with Symmetry-Breaking Guest Anions, Chemistry – A European Journal 21, 2387-2397 (2015)
  3. P. Kozłowski, A. Notario-Estévez, C. de Graaf, X. López and K. Yu. Monakhov, Reconciling valence state with magnetism in mixed-valent polyoxometalates: The case of {VO2F2@V22O54} cluster, Phys. Chem. Chem. Phys. 19, 29767-29771 (2017)
  4. O. Linnenberg, P. Kozłowski, C. Besson, J. van Leusen, U. Englert, and K. Yu. Monakhov, A V16 -type Polyoxovanadate Structure with Intricate Electronic Distribution: Insights from Magnetochemistry. Cryst. Growth Des. 17, 2342–2350 (2017)
  5. A. Notario-Estevez, P. Kozłowski, O. Linnenberg, C. de Graaf, X. Lopez, K. Yu. Monakhov, Decoding the role of encapsulated ions in the electronic and magnetic properties of mixed-valence polyoxovanadate capsules {X@V22O54} (X = ClO4, SCN, VO2F2): a combined theoretical approach Phys. Chem. Chem. Phys. 20, 17847-17858 (2018)
  6. R. Pütt, X. Qiu, P. Kozłowski, H. Gildenast, O. Linnenberg, S. Zahn, R. C. Chiechi and K. Yu. Monakhov, Self-assembled monolayers of polyoxovanadates with phthalocyaninato lanthanide moieties on gold surfaces, Chem. Commun. 55, 13554-13557 (2019)
  7. R. Pütt, P. Kozłowski, I. Werner, J. Griebel, S. Schmitz, J. Warneke, and K. Yu. Monakhov, {P2V3W15}-Polyoxometalates Functionalized with Phthalocyaninato Y and Yb Moieties. Inorg. Chem. 60, 80-86 (2021)

Transport through magnetic molecules

We focus on the theoretical analysis of various quantum effects accompanying electronic transport through nanoscopic systems, which arise due to the presence of magnetic anisotropy. These include such phenomena as the current-induced magnetic switching or the quantum tunneling of magnetization, when the atom/molecule is weakly coupled to an electrode, as well as the Kondo effect, when the coupling is strong.