Abstract
With decreasing a material size, its characteristic properties may diminish at around a nanometric scale. Since nanometric clusters and particles have such crucial sizes, so called an unit of functional element, they will reveal a basic perspective in solid state physics and a new concept for material designing. There are two ways to obtain nanometric size materials: crushing bulk materials and building up from atoms and molecules. In this review, we describe the characteristic features of nano-scale fine Ni particles produced by mechanical milling and chemical leaching, (crushing), and Fe/Ag nano-granular films by using a cluster beam source, (building up). (1) Nonequilibrium bcc and amorphous phases have been realized in Ni particles, being paramagnetic at low temperatures. (2) Fe/Ag granular films have been obtained by direct dispersion of Fe clusters in Ag matrices. They reveal a giant magnetoresistance effect without any heat treatment. The nanometric heterogeneity has been detected by small angle X-ray scattering measurements and distorted Fe clusters in Ag matrices by extended X-ray absorption fine structure measurements.
