Structural and magnetic properties of the double perovskite Sr2MnWO6

The nuclear and magnetic structure and the magnetic properties of the polyc rystalline 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 P4(2)/n, a = 8.0119(4) Angstrom, c = 8.0141(8) Angstrom). Some additional magnetic diffraction peaks were found in the NPD pattern at 10 K, which can be accounted for by anti ferromagnetic ordering of spins at the Mn sites. The magnetic unit cell is doubled in all three u nit axes directions (a = b = 15.9984(8) Angstrom, c = 16.012(2) Angstrom) a nd the manganese moments are coupled antiferromagnetically along the unit c ell axes. The total magnetic moment of Mn2+ is found to be 2.27(7) mu (B). The antiferromagnetic behaviour was confirmed from magnetisation measuremen ts. The transition from a paramagnetic to an antiferromagnetic state takes place at 13.0 +/-0.1 K. (C) 2001 Elsevier Science B.V. All rights reserved.