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Probing Relaxation Dynamics in Five-Coordinate Dysprosium Single-Molecule Magnets
Vijay S Parmar1, Fabrizio Ortu1, Xiaozhou Ma2
1Department of Chemistry, The University of Manchester, Oxford Road, Manchester, M13 9PL, UK.
Chemistry (Weinheim an Der Bergstrasse, Germany)
|March 28, 2020
Summary
Researchers developed new lanthanide single-molecule magnets (Ln SMMs) with high energy barriers over 1200 K. These Dy(III) complexes exhibit enhanced magnetic properties through specific geometric arrangements and halide variations.
Area of Science:
- Inorganic Chemistry
- Materials Science
- Magnetism
Background:
- Single-molecule magnets (SMMs) are crucial for developing high-density data storage and quantum computing.
- Lanthanide ions offer promising magnetic properties due to their large unquenched orbital angular momentum.
- Developing robust lanthanide SMMs with high blocking temperatures remains a significant challenge.
Purpose of the Study:
- To synthesize and characterize a new family of five-coordinate lanthanide single-molecule magnets.
- To investigate the impact of coordination geometry and axial ligands on magnetic properties.
- To explore strategies for enhancing magnetic relaxation dynamics in lanthanide SMMs.
Main Methods:
- Synthesis of five-coordinate Dy(III) complexes with bulky Mes*O ligands and halide anions (Cl, Br, I).
- Structural characterization using X-ray diffraction to determine distorted square pyramidal geometries.
- Magnetic susceptibility measurements and ab initio calculations to evaluate magnetic anisotropy and energy barriers.
Main Results:
- A new series of lanthanide single-molecule magnets [Dy(Mes*O)2 (THF)2 X] were successfully synthesized.
- Complexes exhibit distorted square pyramidal geometry with Dy(III) ions, leading to significant magnetic anisotropy.
- Energy barriers to magnetic reversal exceeding 1200 K were achieved.
- Quantum tunneling of magnetization (QTM) and Raman relaxation were suppressed, with improved performance observed by varying the halide (Cl to I) or through diamagnetic dilution.
Conclusions:
- The five-coordinate dysprosium complexes represent a new class of highly efficient lanthanide single-molecule magnets.
- The distorted square pyramidal geometry and trans-disposed ligands are key to achieving large magnetic anisotropy.
- Tuning the axial halide and employing dilution are effective strategies for optimizing magnetic performance and potential applications in molecular magnetism.
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