Abstract
The effect of magnetic field treatment on the magnetic properties of Ni-Co alloys has been examined with 21 kinds of specimens in the form of ring. It has been found in 1942 that the magnetic properties of some Ni-Co alloys in γ phase region are so much affected by the magnetic treatment, that the maximum permeability of 1050 of 60% Co alloy in an annealed state becomes 16,600 after cooling in a field of 1 Oe. The magnetization and magnetic hysteresis curves of the alloys showing the remarkable effect are of perminvar type, when they were cooled in a weak field from 0.1 to 0.5 Oe, and become more rectangular in form with an increase of the field strength applied during cooling; showing that there are two kinds of domains, one of which can be reoriented in a weak field, while another in a stronger one.
