For high frequency device applications, a systematic study of the soft magnetic properties and magnetization dynamics of (FeCo)-Al alloy thin films has been carried out. A low effective damping parameter alpha(eff) of 0.002 and a high saturation magnetization of about 1,800 emu/cc are obtained at y=0.2 similar to 0.3 for (Fe1-yCoy)(98)Al-2 alloy thin films deposited onto fused silica and MgO(100) at an ambient temperature during deposition. Those films are of the bcc structure with the <110> orientation normal to the film plane. They possess a columnar structure, grown along the film normal. The column width is found to be about 20 nm for y=0.25. It is concluded that the (FeCo)-Al thin films with a damping parameter as low as 0.002 and high saturation magnetization of about 1,800 emu/cc have been successfully fabricated, and that they are potential for future high frequency device applications. (C) 2017 Author(s). All article content, except where otherwise noted, is licensed under a Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/).