| 摘要 |
PROBLEM TO BE SOLVED: To enable utilization due to magnetic resistance effect in low magnetic field by forming raw material powder of a manganese oxide magnetic material and baking the formed product. SOLUTION: Raw material powder 1 of a manganese oxide magnetic material comprising La2 O3 , SrCO3 and MnO2 is calcined at about 900 deg.C for >=12hr to form CO2 gas and carbon is removed from the raw material powder 1 to solidify the powder. The solidified material is pulverized and formed under pressure and the resultant formed product 2 is put on an alumina board 3 in inverted state and baked in an oxygen-containing atmosphere at 1,300-1,400 deg.C for <=2hr and the temperature of the baked material is lowered at a lowering rate of 3-10 deg.C/min to provide the objective perovskite type manganese-based oxide magnetic material having mixed valence, containing Mn, La and Sr at an atom ratio of 1.0: (0.5-0.9):(0.1-0.5). |
