抄録
The mechanism of the negative magnetoresistance effect has hitherto been explained based upon the presence of the Weiss domain proposed by Berger et al. and Sudotov et al. The author discussed the effect from the measuring results of longitudinal and transverse magnetoresistance, dependence of the electrical resistivity on measuring current in zero and applied magnetic fields, hysteresis in longitudinal and transverse magnetic fields, and the magnetic field-rotation effect on the magnetoresistance. The measurements were carried out at 4.2°K for many kinds of high purity iron having the electrical resistivity ratio RRR=R (295°K)/R0(4.2°K) ranging from 35 to 400. It is suggested from these measurements that the large negative magnetoresistance observed in the predominant low-field behavior is substantialy influenced by the domain configuration and domain wall displacement during the magnetization, and indirectly influenced by the varying impurity contents, because the impurity alters the domain configurations and prevents the domain motions. The maximum values of negative magnetoresistance of RRR=35∼400 iron specimens in the longitudinal and transverse fields are 7∼83% and 1∼75% respectively.
