2. Properties of thin films

The macroscopic magnetization of a magnetic material results from atomic magnetic moments, which arrange themselves in parallel (ferromagnetic F) or antiparallel (antiferromagnetic AF in the case of perfect compensation, ferrimagnetic in the case of resultant moment) below a critical temperature called the Curie temperatureT _c for F, the Néel temperatureT _N for AF. Below T _c magnetization follows preferred directions; this is known as magnetic anisotropy. These two properties are referred to as microscopic, or intrinsic, because they depend solely on the local atomic structure of the compounds used. They underlie extrinsic properties such as the appearance of domains and magnetization reversal, presented next.