Magnetic Anisotropy in Flat Ferromagnetic Films: A Review

A review of those characteristics of the anisotropy found in thin Fe–Ni–Co films that are important from a practical viewpoint are presented. Previously published data are supplemented to form a composite ternary diagram of anisotropy field Hk as a function of composition for the alloy system Fe–Ni–Co for 250°C substrate temperature. Anisotropy fields as a function of composition for the three binary alloy systems at other substrate temperatures are included. A composite diagram showing anisotropy field as a function of measuring temperature illustrates the need for temperature stability. Magnetic annealing and aging is discussed. Finally the importance of magnetostriction as a source of the anisotropy is discussed in detail as well as pair ordering. It is concluded that no single source or combination satisfactorily describes the origin of the anisotropy.