Intrinsic magnetic behavior of single and multilayered metal-evaporated films

Metal-evaporated CoNi tapes constituted of one layer and of three layers are studied. In these obliquely deposited films, the angle of the inclined columns on the tape plane conditions the magnetic properties of the medium. The increase of the angle enhances the magnetization, but decreases the coercivity. Multilayered thin films have large magnetization and contemporarily high coercivity. The magnetostatic interactions are positive, or magnetizing, in the triple-layered tape and negative, or demagnetizing, in the single-layered tape. This explains the larger magnetization and remanence of the multilayered tape. The stronger shape anisotropy, due to the larger magnetization, makes smaller the angle of the easy axis on the plane in triple-layered tape, notwithstanding the larger inclination of the columns. The analysis of the magnetization reversal mode indicates that in the triple-layered tape the reversal mechanism is partly coherent rotation, while in the single layered it is more probably incoherent. Such evolution of the basic process of magnetization explains the large coercivity of the multilayered tape.