Paleomagnetic studies have revealed that natural ferrimagnetics, which are constituents of igneous rocks, can be magnetized antiparallel to the magnetizing field. This phenomenon is called self-reversal of magnetization. The question of the actual existence of inversions of the geomagnetic field is still under investigation. This paper considers the physics of the anomalous behavior of natural ferrimagnetic thermomagnetization (TM). The existence of thermomagnetization arising in natural ferrites against the direction of a magnetizing field is experimentally confirmed. It is shown that even after the demagnetization of a ferrimagnetic by alternating magnetic field a significant increase in residual magnetization can occur when it is heated in the absence of a magnetic field.
91.25.Mf Magnetic field reversals: process and timescale
91.25.F- Rock and mineral magnetism
Faculty of Physics, Moscow State University, Moscow, 119991, Russia