Preparation And Magnetic Properties Of Low-dimensional Prussian Blue Analogue Molecular Magnet And Ni Nanowires Composite

Recently, the low dimensional materials have attracted much attention for their distinctive properties and potential application. We synthesized FeCrCr Prussian Blue analogue nanowires and MnFe Prussian Blue analogue nanoparticles in order to investigate their low dimensional properties. We also synthesized Ni nanowires composite to develop microwave absorbing nanomaterials. The primary results are as follow:1. FeCrCr Prussian Blue analogue nanowires with diameters of about 80 nm have been synthesized with anodic oxide film template-based method. The structure analysis of the nanowires indicates a face centered structure. The elemental result indicates that the structure of the nanowires possess Cr vacancies. The infrared spectrum reveals that the oxidation states are Feâ…¡-CN-Crâ…¢and Feâ…¢-CN-Crâ…¡.2. Dc and Ac magnetic properties of the FeCrCr Prussian Blue analogue nanowires are discussed. A negative magnetization and a low temperature spin glass behavior were observed. We consider that the negative magnetization is due to the different temperature dependent magnetization of the ferromagnetic Fe-Cr and anti-ferromagnetic Cr-Cr. The spin glass behavior is caused by the Cr vacancies in the structure and the competition of the ferromagnetic Fe-Cr and anti-ferromagnetic Cr-Cr.3. MnFe Prussian Blue analogue nanoparticles were synthesized by using polyvinyl pyrrolidone (PVP) as a protective matrix. The structure analysis of the nanoparticles indicates a face centered structure. The elemental result indicates that the structure of the nanoparticles possess Fe vacancies. The infrared spectrum and Mossbauer spectrum reveal that the oxidation states are Feâ…¡-CN-Mnâ…¢and Feâ…¢-CN-Mnâ…¡.4. Dc and Ac magnetic properties of the MnFe Prussian Blue analogue nanoparticles are discussed. The infinite, percolating ferrimagnetic cluster expected for fcc lattice is broken into separate yet competing ferri-or antiferro-magnetic clusters due to the Fe vacancies which may be responsible for the low temperature spin glass behavior.5. In developing of the microwave absorbing material, we synthesized Ni nanowires/paraffin wax composite. The corresponding characterization, dc magnetication were reported. The complex permittivity and permeability properties of the Ni nanowires composite have been measured in the frequency range of 2-18 GHz. The resonance peak appeared at around 10 GHz in the permeability spectra. We found that the skin effect was suppressed in the composite, so the resonance peak was the consequence of the natural resonance resulted from the resonance absorption of the spin relaxation of magnetic moment in the Ni nanowires. The permeability spectra were fitted with the Landau-Lifshitz equation and the resonance frequency was calculated by Kittel formula. Our calculation results agree well with the experimental data.