Magnetization of Nickel Under Compressive Stresses and the Production of Magnetic Discontinuities

When nickel is compressed its hysteresis loop approaches a rectangular shape. Several curves for stresses increasing up to the elastic limit have been obtained. At the maximum stress the steep part of the loop is still not vertical and the Barkhausen effect is not appreciably changed by the pressure. Much smaller stresses in an elastically bent wire produce large magnetic discontinuities, hence the existence of contiguous compressed and stretched regions appears to be necessary for the production of the large discontinuities.