Highly stable FeCo/carbon composites: Magnetic properties and microwave response

•The composites of FeCo alloy and carbon nanotubes are highly steady.•The EM absorption can be tuned by adjusting FeCo composition in the composites.•The EM absorption can be tuned by adjusting the layer thickness of the composites.•The coercivity increases with the rise of Co content in the composites.•The saturation magnetization rises in the order of FeCo13@C

Highly steady composites of FeCo alloy and carbon nanotubes have been synthesized by in situ catalytic decomposition of benzene over FeCo alloy nanoparticles generated through procedures of sol–gel fabrication and hydrogen reduction. Magnetic measurement indicates that the coercivity (HC) increases with the rise of Co concentration and the saturation magnetization (MS) rises in the order of FeCo13@C