Syntheses, Magnetic And Ferroelectric Investigations Of Molecule-Based Triangular Ln3Materials

This thesis focuses on the design and synthesis of functional complexes constructed by lanthanides ions and N,N,N’,N’-tetrakis(2-hydroxyethyl)ethylenediamine. Both the magnetic and electric propertiess of the obtained complexes have been investigated in detail.1. An unprecedented molecule-based Dy3-EtOH cluster, which exhibited single-molecule magnetic properties and dielectric properties simultaneously, was obtained under solvent thermal conditions. Two slow magnetic relaxation processes and magnetization steps were found in the magnetic investigation of Dy3-EtOH. The parameters of dipolar and magnetic exchange interactions of Dy3-EtOH which has the practical toroidal arrangement of the local magnetic moments have been calculated in detail with ab initial calculation. Dielectric data displayed a high paraelectric-ferroelectric phase transition and electric hysteresis loops. This work still sheds light on a synthetic route to generate molecular multifunctional materials.2. As a follow-up research work for multiple relaxation processes of Dy3-EtOH, a new solvent-free triangular Dy3cluster has been successfully synthesized and characterized. Magnetic investigations reveal that the new triangular single-molecule magnet (SMM) exhibiting two independent relaxation processes in the absence of solvent molecules. Besides, the magnetic properties of the two magnetic diluted SMMs were also studied, the results of which provided a proper way to investigate multi-steps slow magnetic relaxations.3. Four ferroelectric lanthanide clusters Ln3were obtained from their non-polar point group analogues via solvent modulation, which presents a facile way to obtain new molecule-based ferroelectric materials. All of them exhibited ferroelectric properties with high thermal stabilities, as confirmed by ferroelectric hysteresis loops and anomalies dielectric peaks as well as varying temperature X-ray diffraction and thermal analyses, respectively. Two Gd clusters exhibit large magneto-caloric effect indicating their potential application as MCE and multifunctional devices.