thereof the low loss oxide magnetic material according to the present invention can be obtained by adding to an mg mn zn series ferrite at least one element which is capable of reducing the power loss thereof without decreasing its specific resistance such magnetic material has low power loss while maintaining high specific resistance so that it is able to suppress self heat generation of the deflection yoke core to increase operating reliability of the deflection yoke and at the same time is capable of reducing the ringing phenomenon which has been the main factor of deterioration in the quality of image on the crt with a view to enabling those persons skilled in the art to put the present invention into practice the following examples are presented starting materials were weighed so as to obtain a composition consisting of 45 0 mol of fe 2 o 3 31 0 mol of mgo 7 0 mol of mno and 17 0 mol of zno the powder mixture of these starting materials was calcined for one hour at a temperature of 850 u00b0 c followed by pulverizing the calcined material in a ball mill for four hours thereby obtaining a test material subsequently bi 2 o 3 was added to this test material in a quantity ranging from 0 to 1 5 by weight as shown in table 1 below and the material added with differeing quantities of bi 2 o 3 were uniformly mixed by means of a crush mixer thereafter polyvinyl alcohol solution was added in a quantity of 10.