Field and temperature behavior of remanence in synthetic goethite: Paleomagnetic implications

Abstract

Synthetic powders of pure goethite exhibit an antiferromagnetic behavior and negligible isothermal remanent magnetization up to 4 Tesla. However thermoremanence up to 0.3 Am²kg −1 can be imparted to the samples. High field measurements show median acquisition field of 9–13 T and suggest saturation fields of the order of 10² T. Large increase in remanence at low temperature is an intrinsic feature of goethite. The weak ferromagnetism observed is linked to a bulk origin for spin imbalance rather than to an effect of very fine grain‐size or surface defects. The results are compared with properties of rocks bearing goethite and hematite.