Magnetization of Re-based double perovskites: Noninteger saturation magnetization disclosed

Using static magnetic fields up to 30T, the authors have measured the high-field magnetization in high-quality samples made from Re-based double perovskites: A2FeReO6 (A2=Ca2, Sr2, BaSr) and Sr2CrReO6, with Curie temperatures ranging from 360 up to 610K. The results indicate that the saturation magnetization in these compounds is higher than the assumed spin-only ionic values, 3μB∕f.u. for A2FeReO6 and 1μB∕f.u. for Sr2CrReO6, which is explained by the large orbital contribution to the magnetization. Indirectly, these results show that Re-based double perovskites cannot be described as half-metals.