Magnetic properties of Co-Fe-Ni films

Abstract

A series of Co-rich CoxFeyNiz alloys in both the bulk and the thin-film forms were made. From the X-ray diffraction study, it is found that: (1) when changing from the bulk to the thin-film case, the α–γ phase boundary in the Co–Fe–Ni phase diagram is shifted; (2) the grains in bulk samples are randomly oriented; (3) the grains in the BCC (α phase) films are (1 1 0) textured; (4) the grains in the FCC (γ phase) films are (1 1 1) textured. Then, we find that these structure differences are the main factors to cause different magnetic properties of the two Co–Fe–Ni samples with the same alloy composition, but in different forms, such as the bulk and the thin-film forms, respectively. In this article, magnetic properties discussed include the saturation magnetostriction λs, the saturation magnetization Ms, the coercive force Hc, and the anisotropy field Hk. Besides the structural effect, Ms of the (single-phase) Co–Fe–Ni films is related to the number of valence electrons per atom e/a. In addition, some non-magnetic properties, such as the electrical resistivity ρ and the intrinsic stress S, of those thin-film samples are also studied.