Programming magnetization dynamics in a Dy–croconic acid system

Abstract

The magnetization dynamics of Dy(III) ions were studied in a Dy–croconic acid system from a mononuclear (DyCA) structure to a one-dimensional chain structure ([Dy₂CA₂]_n), achieved by tuning the croconic acid coordination modes while preserving the coordination environment. Thus, the relaxation mechanism changed from the Orbach-process-dominated slow magnetic relaxation in DyCA to the quantum tunneling of magnetization and Raman processes in [Dy₂CA₂]_n, driven by coordination distortion and the enhancement of the transverse magnetic moment. Furthermore, the regulatory mechanisms underlying the Dy(III) magnetization dynamics were further clarified by magnetic dilution experiments and ab initio calculations. The results showed that single-ion anisotropy dominated the magnetic relaxation process, while weak Dy⋯Dy interactions simultaneously suppressed the quantum tunneling of magnetization. This work provides a novel molecular design guideline for the development of high-performance rare-Earth-based molecular magnets.