Electrical steel sheet having insulating coating, method for producing the same, transformer core and transformer using the electrical steel sheet, and method for reducing dielectric loss in transformer

An electrical steel sheet having an insulating coating, the insulating coating being disposed on at least one of surfaces of the electrical steel sheet, the insulating coating having a relative dielectric constant at 1000 Hz of less than or equal to 15.0 and a dielectric loss tangent at 1000 Hz of less than or equal to 20.0,

• wherein the insulating coating includes an insulating coating layer that includes a low-dielectric-loss material dispersed in the insulating coating layer, the low-dielectric-loss material having a dielectric loss coefficient at 1 MHz of less than or equal to 0.10, wherein the low-dielectric-loss material is present as a solid crystalline phase, and
• wherein the low-dielectric-loss material is selected from the group consisting of barium magnesium niobate (Ba(Mg1/3Nb2/3)O3), barium neodymium titanate (Ba4Nd9.3Tl18O54), diopside (CaMgSi2O6), Mg2TiO4, and Nd2Ti2O7.