Magnetic anisotropies in oblique columnar growth of FeCoB films

Abstract

We report on the evolution of anisotropies of FeCoB thin films deposited by magnetron sputtering with different oblique angles increasing from α = 0° to α = 75°. The oblique incidence deposition using the Fe43Co43B14 target leads, under chosen conditions, to columnar growth without bundling. This columnar structure results in a correlated increase in the anisotropy field and of the resonance frequency values, observed with an increasing oblique incidence angle from α = 0° to α = 45°. However, these values decrease from α = 45° to α = 75°. To get a better understanding of the reversal magnetization process, in plane angular distribution of different magnetic parameters was carried out, and the role of easy axis dispersion was especially investigated. The optimized conditions of deposition, leading to controlled high resonance frequencies, could be useful in the design of FeCoB-based microwave devices.