直流磁场作用下液态铝合金热电势的变化

CHANGE OF THERMOELECTRIC POWER OF LIQUID A1 ALLOYS CAUSED BY DC MAGNETIC FIELD

研究了在不同温度下,直流磁场对铝合金热电势的影响.结果显示:当施加在样品两端的磁场强度相差较大时,Al-2.89%Fe合金熔体的热电势逐渐降低.撤除磁场作用后,降低的热电势需要经一段时间,才能缓慢恢复到施加磁场前的初始值.这种现象,在不同温度、不同成分的铝合金熔体(包括纯Al)中被普遍观察到.样品两端磁感应强度平方差越大,热电势变化量越大;在近似均匀磁场作用下,液态铝合金的热电势没有发生变化.根据弱局域化理论,磁场使电子在传输过程中产生附加相位,改变了体系中扩展态电子的分布,从而导致合金熔体的热电势发生变化.

The effect of DC magnetic field on the thermoelectric power of Al alloys at different temperatures was investigated in this work. The results showed that if the magnetic field intensity difference between the two ends of the sample was large, it would lead to a decrease in thermoelectric power of liquid Al-2.89%Fe Al alloys. When the magnetic field was removed, it took a period of time for the thermoelectric power to increase gradually to the initial value. This phenomenon had been observed in other Al alloys melt at different temperature. The higher the square difference of magnetic induction was, the more significant thermoelectric power changed. The approximate homogeneous magnetic field had no effect on the thermoelectric power. According to the theory of weak localization, the magnetic field can change the distribution of extended states electrons which contributes to the change of thermoelectric power