Rotational Relaxation in Nickel at High Frequencies

Measurements of the $\Delta E$ effect and the decrement made by Bozorth, Mason, and McSkimin and by Johnson and Rogers are compared with that expected from a calculation of domain wall relaxations for a distribution of domain sizes as determined by the optical measurements of Williams and Walker. At low frequencies the agreement is good but at high frequencies a second relaxation region is indicated. It is shown that this region is consistent with a domain rotation relaxation and introducing this effect, a good agreement is obtained between theory and experiment for the entire frequency range.