Structural and magnetic properties of the double perovskite Sr2MnWO6

The nuclear and magnetic structure and the magnetic properties of the polycrystalline double perovskite Sr2MnWO6 have been studied. Rietveld analysis of neutron powder diffraction (NPD) data at T=295 K shows that the sample is tetragonal (space group P42/n, a=8.0119(4) A, c=8.0141(8) A). Some additional magnetic diffraction peaks were found in the NPD pattern at 10 K, which can be accounted for by antiferromagnetic ordering of spins at the Mn sites. The magnetic unit cell is doubled in all three unit axes directions (a=b=15.9984(8) A, c=16.012(2) A) and the manganese moments are coupled antiferromagnetically along the unit cell axes. The total magnetic moment of Mn2+ is found to be 2.27(7) μB. The antiferromagnetic behaviour was confirmed from magnetisation measurements. The transition from a paramagnetic to an antiferromagnetic state takes place at 13.0±0.1 K