Residual stress optimization in FeAlN pole materials

Abstract

Rf-diode reactively sputtered FeAlN films, which are good candidates for high-density write head pole materials, usually have very large compressive residual stresses. In this paper we describe our efforts to lower the residual stress, and study the effects of lowered stress on the magnetic properties of the FeAlN films. It is found that increasing the total sputtering pressure while keeping the optimum Fe to N arrival flux constant can lower the residual stress. The films with lowered residual stress, however, are more susceptible to the formation of stripe domains which are detrimental to the magnetic properties. In order to avoid these stripe domains, the thickness of the film should not exceed the critical stripe domain onset thickness. For applications where thicker films are desired, we demonstrate that laminating single layer films whose thicknesses do not exceed the critical thickness produces films with good magnetic properties and acceptable residual stress.

Soft magnetic properties and high frequency permeability in [CoAlO/oxide] multilayer films

“…From the shapes of the two axis loops, it could be seen that the three samples had the characteristic of magnetic anisotropy, especially for the 35 nm film that had the narrowest hard axis loop. Their easy axis loops showed low saturation states at the fields below 100 Oe, apparently similar to the situation where the ripple domains existed in the films [17]. Figure 1(d) gives the coercivities (easy axis: H ce and hard axis: H ch ) and effective anisotropic field (H k ) of the CoAlO single layer films at different thicknesses.…”

Magnetization dynamics of weak stripe domains in Fe–N thin films: a multi-technique complementary approach

“…It is now agreed that SDs appear in ferromagnetic films with perpendicular anisotropy K u . This latter can originate from magnetocrystalline and/or stress aniso tropy [7][8][9]. Other parameters such as the film thickness t f , the saturation magnetization M s and the exchange stiffness A also play a significant role on the nucleation and characteristics of SDs [10].…”

High frequency microwave characteristics of amorphous FeCoNiB–SiO2 thin films

“…In the meantime, the bombarding atoms can reach the substrate directly and have enough energy to overcome the surface energy barrier when the argon pressure gets low enough. Thus, within the critical thickness [25], denser texture and smaller grain size can be obtained in this nar- Fig. 9.…”