APPLICATION OF FERRIMAGNETIC RESONANCE HEATING TO PALEOINTENSITY DETERMINATIONS

The first results for the ancient intensity of the geomagnetic field a re presented using ferrrimagnetic resonance at 8.2 GHz to remagnetize the samples. Because the microwave dissipation is overwhelmingly confi ned to the magnetic grains, their temperature can approach the magneti c transition temperature, whereas the rest of the material remains at less than 100 degrees C. As a result, mineral alteration owing to heat ing of the nonmagnetic matrix, which leads to large errors in the inte nsity, is completely avoided.