Study on the self-organizing arrangements of nano-scale magnetic particles in Cu-base alloys and their mechanisms

纳米颗粒铁磁材料具有由铁磁细颗粒和金属或非金属基体组成的异质微结构。因此，微结构可能会对其物理性能产生重大影响，例如巨磁阻（GMR）效应。尽管如此，到目前为止，微观结构和磁性能之间的关系已经在少数情况下进行了研究。本研究的目的是使密切调查的关系，在Cu-Ni-Fe合金，利用透射电子显微镜（TEM）和SQUID磁性测量。研究表明，在巨磁电阻效应中，由超顺磁性颗粒组成的微结构优于含有细铁磁性颗粒的微结构。

Nano-granular ferromagnetic materials have heterogeneous microstructures comprising ferromagnetic fine particles and metallic or non-metallic bases. Accordingly, the microstructures are likely to give significant influences to their physical properties such as the giant magneto-resistance(GMR) effect. Despite the anticipation, the relationship between microstructure and magnetic properties has been investigated in few cases so far. The present study was aimed to make a close investigation to the relationship in Cu-Ni-Fe alloys, using transmission electron microscopy(TEM) and SQUID magnetic measurements. This investigation revealed that microstructure consisting of super-paramagnetic particles surpassed that containing fine ferromagnetic particles in the GMR effect.