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系列陶瓷氧化物La0.67Sr0.33FexMn1-xO3（0.055x0.33）通过共沉淀法工艺合成获得.经X射线衍射分析表明，所得氧化物均为单相，属三方结构.在零场和外加磁场下的四极法电阻测试结果表明：所有样品都具有较大的磁电阻效应，当x<0.13时，样品的电阻率-温度曲线中均出现电阻率峰（电阻率出现从半导体性向金属性的转变），该电阻率峰处的温度（Tp）随x的增大而向低温区移动，磁电阻效应是负值;x＝0.23时，样品已呈半导体性，磁电阻效应仍是负值;然而x＝0.33时，样品虽也表现为半导体性，但其中的磁电阻效应出现奇特的正负交替转换.
The series of ceramic oxides La0.67Sr0.33FexMn1-xO3 (0.055x0.33) were synthesized by the coprecipitation method. The X-ray diffraction analysis showed that the oxides were single phase and had a tripartite structure. The results of the four-pole resistance test show that all the samples have large magnetoresistance effect. When x <0.13, the resistivity peak appears in the resistivity-temperature curve of the sample (the resistivity appears from semiconducting to metallic (Tp) of the resistivity peak shifts to low temperature region with the increase of x, the magnetoresistance effect is negative; when x = 0.23, the sample has been semiconducting, the magnetoresistance effect is still negative; However, when x = 0.33, the samples also showed semiconducting properties, but the magnetoresistance effect alternated between the positive and the negative.