Programming magnetization dynamics in a Dy-croconic acid system

Abstract

Magnetization dynamics of Dy(III) ions were studied in a Dy-croconic acid system from a mononuclear (DyCA) to a 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 of DyCA to the quantum tunneling of magnetization and Raman process of [Dy₂CA₂]_n, driven by coordination distortion and the enhancement of the transverse magnetic moment. Furthermore, the regulatory mechanism underlying 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 the weak Dy•••Dy interactions simultaneously suppress the quantum tunneling of magnetization. This work provides a novel molecular design guideline for the development of high-performance rare-earth-based molecular magnets.