氰根桥联Ni(Ⅱ)-Fe(Ⅲ)类纳米分子磁体磁性及穆斯堡尔谱研究

Magnetism and Mssbauer spectra of cyanide-bridged Ni-Fe nano-molecular-magnets

用溶液共沉淀法合成了普鲁士蓝类分子磁体化合物Ni3[Fe(CN)6]2.8.2H2O,使用透射电子显微镜、元素分析仪、X射线荧光光谱仪、X射线衍射仪、傅里叶变换红外光谱仪、超导量子干涉仪对配合物的结构及磁性能进行了分析研究.结果表明:产物为颗粒状,粒径为20—30nm,晶体结构为面心立方;当温度从60K降至5K时,配合物表现为从顺磁相到铁磁相的转变,相变温度为22.8K,分析得出Ni(Ⅱ)和Fe(Ⅲ)之间通过氰根以铁磁形式耦合.采用变温穆斯堡尔谱对其磁性机理进行了分析,得到了与磁测量相符合的结果.

Nanoparticles of Prussian blue analogues Ni3 [ Fe（CN）6 ]· 8.28H2O have been successfully synthesized by co-precipitation method. The nanoparticles were characterized by elemental analysis, X-ray diffraction, Fourier transform infrared spectrometry and transmission electron microscopy. Magnetic measurement was carried by superconducting quantum interference device magnetometer and the result showed the the transition temperature Tc = 22.8 K. The interaction between Ni（ Ⅱ ） and Fe（Ⅲ） was identified to be a kind of ferromagnetic coupling and was clearly explained by molecular orbital theory. The Mossbauer spectra have been used to explain the origin of magnetism.