Magnetic Properties Of Multi-metal Cyano-bridged And Oxalate Complexes

Design and synthesis of molecule-based magnets refer to many fields such as physics, chemistry, life sciences and materials.Molecular magnet means molecular configuration spin Vector(free radical or Paramagnetic ions) Synthesised in the solution with the properties of Magnet,which has the properties of Spontaneous magnetization under the Critical temperature.The common method of obtaining Molecular magnet is to choose the correct ligand and Bridging groups Magnetic ions to form the compound.we design molecular magnet through changing different kinds of ligand,Bridging groups and Magnetic ions to change the structure of compound and control their Magnetic.The magnetic of compound is related to the magnetic of magnetic ions and the properties of Bridging groups.cyano-bridged and complexes play an important role due to their special structure and outstanding magnetic properties as molecule-based magnets. In this thesis, the magnetic measurements and structural measurements are performed to study the magnetic properties, microstructure and magnetic coupling mechanism in molecular magnets based on transition metal complexes. We discover the compensation temperature in NBu4ZnII0.04FeII0.96[FeIII(ox)3], which is also confirmed reasonably in terms of the qualitative analysis. In the thesis, we have obtained the results in the following aspects:1. Multimetallic prussian blue compounds Ni0.75Cu0.75[Fe(CN)6]·6.3H2O and was prepared by co-precipitation. The magnetic studies results show that the compound is ferromagnetic magnets, undergo a paramagnetic to the ferromagnetic transition temperature at 21.77K.The paramagnetic curie temperatureθ, residual magnetization Mr, and coercive field Hc are different from bimetallic Prussian Blue Compounds Ni3[Fe(CN)6]2·xH2O,Cu3[Fe(CN )6 ]2·11.6H2O.So in the multi-nuclear Prussian Blue Compounds,we can control the magnetic(Critical temperature,Saturation magnetization,coercive field) of compound through changing the type of transition metal ions and adjusting the proportion of different kinds of transition metal ions.2.A mixed-metal compound NBu4ZnII0.03FeII0.97[FeIII(ox)3] was prepared by co-precipitation. The magnetic susceptibilities indicate that there exist a ferrimagnetic exchange interaction in the compound, and magnetic transition at 23K. A compensation temperature has found with the field being less than 1KOe. When the temperature is greater than 50K, the relationship between temperature and susceptibility follows Curie - Weiss law. The observed value of coercive field (Hc) and remanent magnetization (Mr) for the compound are 15KOe and 572.2 cm3·G·mol-1.A mixed-metal compound NBu4FeII0.07MnII0.93[FeIII(ox)3]was prepared by co-precipitation.we research it's structure and magnetic,at last,we compare the difference of the two samples.