A Mn-Zn-Fe ferrite layer, several hundred nanometers thick, was deposited on the surface of Fe-3.5Si-4.5Cr (mass%) powder particles as an insulating material by an ultrasonic enhanced ferrite plating method. The compositions of the Mn-Zn-Fe ferrite layer were Mn0.18Zn0.27Fe2.55O4, Mn0.38Zn0.25Fe2.37O4, and Mn0.54Zn0.24Fe2.22O4. The core loss (P-cv) performances of the compacted cores and magnetic properties of the core-shell structured powders were evaluated. All the ferrite-coated cores exhibited a saturation flux density (B-s) in the range of 1.54-1.56 T derived from their soft magnetic metal and ferrite composition. All ferrite-coated cores annealed at 773 K exhibited a constant permeability mu' in the frequency range up to 50 MHz owing to the insulating effect of the ferrite layer, and the Mn0.54Zn0.24Fe2.22O4 ferrite-coated core exhibited the highest real permeability mu' of 56 at 50 MHz. The core loss of the Mn-Zn-Fe ferrite-coated Fe-3.5Si-4.5Cr cores was 604-738 kW/m(3) at 100 kHz and 50 mT, which was much smaller than that obtained for the Fe-3.5Si-4.5Cr core without a ferrite layer (3617 kW/m(3)). The eddy-current loss (P-e) of the Mn-Zn-Fe ferrite-coated Fe-3.5Si-4.5Cr cores considerably decreased compared with those of the non-coated Fe-3.5Si-4.5Cr core owing to the insulating properties of the ferrite layer. (C) 2018 The Society of Powder Technology Japan. Published by Elsevier B.V. and The Society of Powder Technology Japan. All rights reserved.