is possible to obtain a product superior in magnetic permeability prevented from cracking or chipping even if thin and superior in reliability further this contributes to the reduction of size and reduction of cost of the product next the present invention will be explained in further detail by more specific examples but the present invention is not limited to these examples as the materials 48 0 mol of fe 2 o 3 19 3 mol of mgo 7 1 mol of cuo and 25 6 mol of zno were weighed then wet mixed by a ball mill for 16 hours to obtain a raw material mixture next the raw material mixture was prefired at 900 u00b0 c for 2 hours to obtain a prefired material then was wet pulverized by a ball mill for 16 hours to obtain a pulverized material next 10 wt of an 6 aqueous solution of polyvinyl alcohol was added as a binder to 100 wt of the pulverized material and granulated to obtain a granulated material this was pressed at a pressure of 1 ton cm 2 to a toroidal shape to obtain a shaped article further for the test of the bending strength the material was pressed at a pressure of 1 ton cm 2 to a rod shape of 5 u00d7 5 u00d7 500 mm to obtain a shaped article next these shaped articles were placed in a sintering furnace for sintering this sintering was.