The magnetism of AlxFe2−xGeO5 from x = 0.09 to x = 0.91 with andalusite structure was examined. The magnetic properties of AlxFe2−xGeO5 at low temperatures were found to be weak ferromagnetic-like state for x< 0.3 and spin-glass state for x> 0.3. The small spontaneous magnetization that appears in the weak ferromagnetic-like phase would be due to the presence of Dzyaloshinsky-Moriya interaction or to the difference in the magnitude of the magnetic moment of Fe3+ in the octahedral and trigonal bipyramidal sites. The appearance of the spin-glass phase indicates that the dilution of Fe ions by Al ions in AlxFe2−xGeO5 causes the competition between ferromagnetic and antiferromagnetic interactions. The x dependence of the site occupancy of Fe ions suggests that Fe2GeO5 with andalusite structure cannot be synthesized.
@article{arxiv.2202.01491,
title = {Magnetism of Al$_x$Fe$_{2-x}$GeO$_5$ with Andalusite Structure},
author = {K. Kakimoto and S. Takada and H. Ohta and Y. Haraguchi and M. Hagihala and S. Torii and T. Kamiyama and H. Mitamura and M. Tokunaga and A. Hatakeyama and H. Aruga Katori},
journal= {arXiv preprint arXiv:2202.01491},
year = {2022}
}