Reversible Susceptibility of Hematite Carrying Various Types of Remanent Magnetization and Memory

The reversible susceptibility of large single crystals of hematite carrying different intensities of various types of remanent magnetization, i. e., IRM, TRM and ARM has been measured in a small A C magnetic field (H≈3œ) using a transformer bridge. In a stoichiometric αFe2O3 specimen, reversible susceptibility has also been measured before and after cooling and heating through the Morin transition. The results of these experiments have revealed that reversible susceptibility decreases steeply with increasing IRM but that it is independent of the magnitude of TRM, ARM and memory of any types of remanence except when TRM and ARM are almost saturated. It may be concluded that the blocking mechanism of TRM and ARM is similar to the mechanism of memory of remanence but completely different from that of acquisition of IRM. It may be inferred that stable TRM, ARM and memorized remanence are carried as magnetically hard particular regions in the crystals while soft remanence is due to the more usual process of the domain wall movement.