FeCo soft magnetic, electrically insulated nanopowders

•FeCo/Al2O3 electrically insulated nanopowders were prepared by chemical synthesis.•The nanoparticles consist on crystalline FeCo compound (bbc) and amorphous Al2O3.•The presence of Al2O3 increases dramatically the resistivity of FeCo nanopowders.•The high values of saturation magnetisation were combined with low coercivities.•The properties recommend FeCo/Al2O3 nanopowders for high frequency applications.