Composite soft magnetic material

A composite soft magnetic material comprising

• soft magnetic metal particles having a mean particle diameter of 5-100 .mu.m and a coercive force of up to about 0.5 Oe as measured in bulk form,
• a layer of high resistance soft magnetic substance having an electric resistivity of about 10.sup.2 .OMEGA.-cm or higher and a mean particle size of abut 0.01-2 .mu.m, and
• a 3 to 300 nm thick layer of non-magnetic metal oxide formed by diffusion intervening between each soft magnetic particles and said high resistance soft magnetic substance layer;
• wherein said material has a core loss of about 350-3,000 kW/m.sup.3 at 0.1 mT, 100 kHz and about 5-100 kW/m.sup.3 at 0.1 mT, 10 kHz
• wherein said composite material is obtained by heat treating said soft magnetic metal particles in an oxygen atmosphere, thereby forming a diffusion layer of non-magnetic metal oxide on said particle surface, coating said particles with said high resistance soft magnetic substance and sintering said coated particles under pressure.