The transverse magneto-resistance effect in single crystals of iron

The experiments to be described in this paper, deal with the change of resistance of single crystals of iron caused by a magnetic field perpendicular to the direction of the current. In two earlier papers, it has been shown that both the phenomena of magneto-striction and change of resistance in a longitudinal magnetic field were very different when measured in different directions in the crystal. And the results led to the conclusion that the change of resistance in the latter case was due to the change of orientation of the atoms accompanying magnetization, any direct influence of the field on the resistance being negligible. With these results in mind it seemed important to determine how the change of resistance in a transverse magnetic field depended on the crystal structure, and whether this more complicated effect, dealing with two directions in the crystal instead of one, would fit in with the results previously obtained. Many measurements of this phenomenon have been made for soft iron, and it has generally been accepted that there is only a decrease of resistance, slow at first, then rapid, finally approaching a saturation value. Occasionally an initial increase has been found, but this has not been considered genuine, being accounted for by the presence of a longitudinal component of magnetization due to imperfect orientation of the rod in the magnetic field.