Study on mesoscopic physical phenomenon in many particle systems by electron holography

我们使用日立HF-2000透射式电子显微镜进行电子全息实验。双棱镜丝安装在显微镜的两个中间透镜之间，并在导线上施加几十到100伏的电压。在确认干涉条纹的重复性后，我们首先使用直径约1μm的乳胶粒子作为样本。重建的相图显示了粒子周围的等电势曲线，这被解释为表示粒子周围的静电场。接下来，我们用同样的技术观察了Nd-Fe-B合金粉末。从重建的位相图像可以看出，大约4.1×10；-14；gt；Wb的磁通已经渗透到样品尖端约1μm的区域。此外，我们还利用等离子体气体凝聚(PGC)技术合成了单分散的Co/CoO团簇。这种团簇组装表现出很强的单轴磁各向异性。磁弛豫行为的详细观察表明，宏观量子隧道效应在8K以下发生。此外，利用PGC技术首次产生了煤金属间化合物合金团簇。通过控制加工条件，可以同时改变团簇的组成和大小。富钴合金团簇表现出明显的铁磁行为。

We employed Hitach HF-2000 transmission electron microscopy for electron holography experiments. The biprism wire was installed between the two intermediate lenses of the microscope, and several ten to 100 voltages was applied to the wire. Having confirmed the reproducibility of the interference fringes, we first used latex particles of approximately 1μm in diameter as a specimen. Reconstructed phase images exhibited equipotential curves around the particles, which was interpreted to represent the electrostatic field around the particles. Next, we observed Nd-Fe-B alloy powders with the same technique. From the reconstructed phase image, it was concluded that a magnetic flux of approximately 4.1x10^<-14> Wb penetrated into the about 1μm area of the tip of the specimen.In addition, we synthesized monodispersive Co/CoO cluster assembly using plasma gas condensation (PGC) technique. This cluster assembly exhibited strong uniaxial magnetic anisotropy. The detailed observation on the magnetic relaxation behavior indicated macroscopic quantum tunneling effect is operating below 8K.In addition, CoAl intermetallic alloy clusters were generated by the PGC technique for the first time. By controlling processing conditions, it was possible to change both the composition and size of the clusters. The Co-rich alloy clusters clearly exhibited ferromagnetic behavior.