Resolving the Internal Magnetic Domain Structure of Cloudy Zone Tetrataenite

Abstract

Recent advances in magnetic imaging can directly capture the internal magnetization of natural and synthetic materials at resolutions <10 nm. This capability opens new possibilities to determine the magnetic domain state of ferromagnetic minerals that are fundamental for recording and retaining paleomagnetic records. Here, we present the highest resolution magnetic contrast images to date of tetrataenite islands in the cloudy zone of the Esquel pallasite meteorite obtained using circular dichroic soft X-ray ptychography. These images, obtained with 4.4 nm spatial resolution, provide new insights into the magnetic structure of the cloudy zone, namely the prevalence of multidomain states, magnetostatic interactions, and islands with multiple “easy” magnetic axes. Our results demonstrate that the non-interacting, single-domain models used to derive cloudy-zone paleointensities in previous studies need to be updated and re-evaluated. We additionally highlight the potential of high-resolution ptychography to enhance our understanding of paleomagnetic remanence carriers in future work.