1,3,- 1Department of Earth Sciences, Uppsala University, Sweden (julia.sordyl@geo.uu.se)
- 2Department of Materials Science and Engineering, Uppsala University, Sweden
- 3Department of Geosciences, Swedish Museum of Natural History, Stockholm, Sweden
- 4Department of Chemistry - Ångström Laboratory, Uppsala University, Sweden
- 5Department of Physics and Astronomy, Uppsala University, Sweden
- 6Sweden and Wallenberg Initiative Materials Science, WISE, Uppsala University, Sweden
Magnetic properties of ferrimagnetic minerals have been studied in detail over the years. By contrast, the magnetic properties of paramagnetic minerals containing rare earth elements (REE) remain largely unexplored, even though the presence of particular rare-earth ions can give rise to complex magnetic behavior due to their unpaired 4f electrons. Consequently, filling this knowledge gap is becoming increasingly important in light of the enormous interest these minerals have attracted in recent years because of their economic value. The primary goal of this study is to characterize the intrinsic magnetic behavior of selected REE minerals at the grain scale and in relation to their crystal structures.
Six REE-bearing minerals from various Swedish localities were investigated: monazite-(Ce), xenotime-(Y), ferriallanite-(Ce), bastnäsite-(Ce), cerite-(CeCa) and fluorapatite. Electron microprobe analysis and X-ray diffraction methods were used to determine mineral chemistry and confirm crystal structures. Magnetic properties were characterized via field- and temperature- dependent magnetization measurements.
Field-dependent magnetization measured at 2 K revealed the absence of a hysteresis loop in all minerals except ferriallanite-(Ce), which exhibits a small hysteresis loop. This behavior is primarily attributed to the presence of Fe2+ and Fe3+ ions in ferriallanite-(Ce). The preliminary results show that the effective magnetic moments (μ_eff) obtained from temperature-dependent measurements are in good agreement with calculated free-ion magnetic moments (μ_calc), suggesting that paramagnetic rare-earth ions represent a major contribution to the observed magnetism.
These results provide fundamental knowledge of the intrinsic magnetic properties of selected REE-bearing minerals and improve our understanding of their crystal-chemical controls on their magnetism. Moreover, these insights form a basis for further interdisciplinary studies exploring the potential of designing novel functional materials inspired by naturally occurring compositions.
How to cite: Sordyl, J., Corona, A., Almqvist, B., Holtstam, D., Sahlberg, M., Cedervall, J., Sarkar, T., Herper, H., Vishina, A., and Eriksson, O.: Crystal-chemical controls on the magnetic behavior of REE-bearing minerals, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-13171, https://doi.org/10.5194/egusphere-egu26-13171, 2026.
