An experiment relating to rotational remanent magnetization and frequency of demagnetizing field

Summary. Several tests have been carried out to investigate how the generation of rotational remanent magnetization depended on the frequency of the applied demagnetizing field. The equipment used is described. The investigation was carried out using two specimens, one being a synthetic specimen of magnetite, and the other a cylindrical rock sample. These specimens gave virtually identical behaviour with varying frequency, unlike the differing behaviours reported previously by Wilson & Lomax. For each of the separate alternating field frequencies used (ranging from 50 to 1210 Hz), as the rotational speed of each specimen was reduced from 0.1 cycle s⁻¹, the corresponding rotational remanent magnetization increased to a maximum value when the rotational speed was in each case just a little greater than 0.01 cycle s⁻¹, after which the rotational remanence decreases as the rotational speed decreases.