W. Weber, C.H. Back, et al.
Nature
The natural remanent magnetization of andesitic pumice erupted from the Nevado del Ruiz volcano (Colombia) in 1985 is reversed with respect to the present geomagnetic field because of self-reversal. Laboratory thermoremanent magnetization acquired in fields of < 1 mT fully re-establishes the self-reversal mechanism. Hysteresis experiments indicate that the mechanism is caused by antiparallel coupling as a result of exchange interaction in two haemoilmenite phases of different composition. The weak critical field needed to suppress this self-reversal effect (≈ 1.2 mT) can be explained by a domain wall model. © 1990.
W. Weber, C.H. Back, et al.
Nature
R. Allenspach, M. Stampanoni, et al.
Physical Review Letters
V. Scagnoli, U. Staub, et al.
Conference on Magnetism (ICM) 2003
R. Allenspach, A. Bischof, et al.
Applied Physics Letters