In-Field and Zero-Field Relaxation Dynamics of Dysprosocenium in Solution

Area of Science:

• Molecular Magnetism
• Quantum Dynamics
• Materials Science

Background:

• Single-molecule magnets (SMMs) are crucial for advanced magnetic storage and quantum computing.
• Current research focuses on increasing effective barrier (Ueff) and hysteresis temperature (TH) through molecular design.
• The influence of the local environment on SMM magnetic relaxation remains underexplored.

Purpose of the Study:

• To investigate the effect of solvent environment on the magnetic relaxation dynamics of a specific dysprosium-based SMM, [Dy(Cp^ttt)2][B(C6F5)4].
• To differentiate between high-temperature (Raman-I) and low-temperature (quantum tunneling of the magnetization - QTM) relaxation mechanisms under varying environmental conditions.

Main Methods:

• Dissolving the SMM [Dy(Cp^ttt)2][B(C6F5)4] in two distinct solvents: difluorobenzene (DFB) and dichloromethane (DCM).
• Characterizing magnetic relaxation properties using techniques sensitive to phonon-driven processes and quantum tunneling.
• Comparing relaxation rates in solution (dilute and concentrated) with polycrystalline samples.

Main Results:

• No significant change in phonon-driven Raman-I relaxation at higher temperatures was observed across different environments.
• The frozen-solution environment led to an increased rate of quantum tunneling of the magnetization (QTM) due to a larger avoided level crossing.
• A substantial decrease in Raman relaxation rate at low temperatures was noted for concentrated DCM and polycrystalline samples, attributed to altered low-energy phonon spectra.

Conclusions:

• The local solvent environment can significantly influence the quantum tunneling of the magnetization (QTM) in SMMs, even without altering high-temperature relaxation.
• Changes in the low-energy phonon spectrum of the surrounding matrix play a critical role in low-temperature magnetic relaxation.
• Perturbing the local environment offers a complementary strategy to molecular design for tuning SMM performance.