Rare earth materials have been widely applied in the medical field, such as magnetic anastomosis and magnetic anchoring technologies based on the potent magnetic properties of NdFeB, gadolinium-based serial nuclear magnetic contrast agents, and tumor fluorescent imaging based on rare earth elements, etc. Meantime, rare earth-based molecule magnets are the focus of research on novel ultra-high-density information storage materials. High-density magnetic material for rapid retrieval and writing of data should have a hard hysteresis loops with large coercive field and remanence at zero-field. However, for single-molecule magnets, a hard hysteresis loop is difficult to achieve due to the quantum tunneling of the magnetization, especially at zero-field.
Recently, the team led by Distinguished Professor Zheng Yanzhen from the First Affiliated Hospital of Xi 'an Jiaotong University (XJTU) published an Article entitled Suppression of Zero-field Quantum Tunneling of Magnetization by a Fluoride Bridge for a "Very Hard" 3d-4f Single-molecule Magnet in Matter. The First Affiliated Hospital of XJTU is the first affiliation. Professor Zheng Yanzhen is the corresponding author. Ling Bokai and Zhai Yuanqi are the first authors. Professor Lyu Yi and Professor Zhang Xufeng from our hospital are the co-authors of this article. This is another successful cooperation between bilateral sides after they jointly received the first prize of Chinese Medical Science and Technology Award. Subsequently, both sides will jointly carry out scientific research related to biological effects of magnetic field.
In this study, a central fluorido bridge was introduced into 3d-4f single-molecule magnet to create ferromagnetic couplings, which effectively suppressed the quantum tunneling effect at zero-field and obtained a high-performance single-molecule magnet with a coercive field of 1.3 T and more than 97% remanence, which is extremely rare.
Subsequent magnetic theory calculation found that the introduction of fluorido bridge creates the ground magnetic moment among Dy-Dy ferromagnetic coupling, and Dy-Cr antiferromagnetic coupling leads to a large ground magnetic moment (10.7μB) in DyC clusters. Through Zeeman splitting graph, the authors found that the large spin ground momentum is crucial to suppress quantum tunneling at zero-field. In this study, afluorido bridge was successfully introduced into 3d-4f complex by precursor method, and the fluorido content was accurately determined by several characterization methods, providing valuable reference for subsequent synthesis of fluorido bridge-rare earth clusters with medical application value.
Article link:https://doi.org/10.1016/j.matt.2022.07.009
