Lanthanide single molecule magnets: relation between crystal packing and tunnelling relaxation time

Area of Science:

• Quantum physics
• Materials science
• Chemistry

Background:

• Single-molecule magnets (SMMs) are crucial for developing advanced magnetic storage and quantum computing technologies.
• Understanding quantum tunnelling relaxation is key to optimizing SMM performance.
• Crystal packing significantly influences the magnetic properties of SMMs.

Purpose of the Study:

• To investigate the impact of crystal packing motifs on quantum tunnelling driven relaxation time in SMMs.
• To identify optimal crystal structures and magnetic topologies for faster SMM relaxation.
• To provide chemical design strategies for enhanced SMM performance.

Main Methods:

• Utilized an *ab initio* model to calculate quantum tunnelling relaxation times.
• Analyzed a large dataset of 13,510 crystal packing structures from the Cambridge Structural Database.
• Correlated unit cell parameters, space group symmetry, and magnetic topology with relaxation times.

Main Results:

• Lower symmetry crystal groups and lower dimensional magnetic topologies lead to reduced tunnelling relaxation times.
• Non-collinear magnetic moment arrangements in higher symmetry groups are less favorable for relaxation.
• Identified specific packing arrangements and chemical strategies (e.g., aliphatic chains, bulky counterions, planar ligands) that promote desired structural anisotropy.

Conclusions:

• Crystal engineering of SMMs through strategic packing motif selection is a viable approach to tune quantum tunnelling relaxation.
• Lower symmetry and lower dimensionality are key factors for designing SMMs with faster demagnetization times.
• The findings offer a new perspective for the rational design of high-performance SMMs.