Recent Concepts in Materials Science
Nanostructures deal with objects and structures that are in the 1—100 nm range. In many materials, atoms or molecules cluster together to form objects at the nanoscale. This leads to interesting electromagnetic, optical and mechanical properties. The term 'nanostructure' is often used when referring to magnetic technology. Microstructure is defined as the structure of a prepared surface or thin foil of material as revealed by a microscope above 25× magnification. It deals with objects from 100 nm to a few cm. Most of the traditional materials (such as metals and ceramics) are micro structured. Macrostructure is the appearance of a material in the scale millimetres to meters—it is the structure of the material as seen with the naked eye. Atomic structure deals with the atoms of the materials and how they are arranged to give structure of molecules, crystalline solidsetc., The length scales involved are in angstroms (0.1 nm). The way in which the atoms and molecules are bonded and arranged is fundamental to studying the properties and behaviour of any material. Crystallography is the science that examines the arrangement of atoms in crystalline solids. Crystallography is very much useful for materials scientists. Polymers display varying degrees of crystallinity and many are completely non-crystalline. Glass, some ceramics, and many natural materials are amorphous, not possessing any long-range order in their atomic nuclei.