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测定了面心立方结构Fe-Mn-Al,Fe-Mn-Cr合金的电阻率及磁化率与温度的关系,这些合金均呈现顺磁性-反铁磁性转变,并伴有电阻率-温度关系的反常变化.电阻率测定的结果说明,在Néel温度T_N以下,由于反铁磁有序散射,使电阻率反常增大,dρ/dT减小或变为负值,ρ-T曲线向上弯曲,反常电阻率随T_N的下降和X-T曲线峰值的升高而增大.Al的加入量对反铁磁转变引起的电阻率变化有强烈的影响,随Al浓度的增加,反常电阻率急剧增大,这可能与Al使合金中Fe离子位置存在较大局域净磁矩有关.Cr对反铁磁电阻率的影响远较Al小.本文的实验结果揭示,基于顺磁性-反铁磁性转变,研制一种温度系数较小的Fe-Mn-Al-Cr系新电阻合金是可能的。
The resistivity and magnetic susceptibility of the face-centered cubic Fe-Mn-Al and Fe-Mn-Cr alloys were measured. The alloys exhibited paramagnetic-antiferromagnetic transition accompanied by resistivity-temperature relationship The results of the resistivity measurement show that under the Nel temperature T_N, the resistivity increases abnormally and the dρ / dT decreases or becomes negative due to the antiferromagnetic ordered scattering, and the ρ-T curve curves upwards and abnormally The resistivity increases with the decrease of T_N and the increase of the peak of XT curve.The addition of Al has a strong influence on the change of resistivity caused by the antiferromagnetic transition, and the anomalous resistivity increases sharply with the increase of Al concentration Which may be related to the existence of a large local net magnetic moment at the position of Fe in Al alloy.The effect of Cr on the antiferromagnetic resistivity is far less than that of Al.The experimental results show that based on the paramagnetic-antiferromagnetic transition, Fe-Mn-Al-Cr based new resistance alloys with a small temperature coefficient are possible.