Ferrimagnetic order in Ca2FeMoO6

The double perovskite Ca2FeMoO6 is a poor metal which orders magnetically a t 345 K. The Fe-57 Mossbauer hyperfine field and isomer shift at 4.2 K (48 T and 0.70 mm/s relative to alpha-Fe) indicate an Fe3+ configuration 3d(5 u p arrow) which is strongly hybridized with the Mo 4d(down arrow)t(2g) orbit als. The saturation magnetization of 3.6 mu(B)/formula is consistent with n eutron diffraction measurements which indicate iron and molybdenum moments of 4.0(1) and -0.2(3)mu(B) per iron or molybdenum, respectively. The sample exhibits approximately 6% cation disorder relative to the ideal NaCl-type order of Fe and Mo in the double perovskite structure. (C) 2000 American In stitute of Physics. [S0021- 8979(00)90408-0].