“…Among the candidates, FeCo alloys, the outstanding soft-magnetic materials, have attracted great interest due to the high saturation magnetization (up to 2.45 T), low magnetostriction, high resistivity, small coercive forces and high Curie temperature [5][6][7]. FeCo composites, such as Y 2 O 3 /FeCo shell/core nanocomposites [8], Al 2 O 3 and C-coated FeCo nanocapsules [9,10], have been developed and an expected microwave absorption ability is obtained because of a better electromagnetic match.…”