A magnetic, electronic and structural study of the double perovskites Ba2REMoO6 (RE = Sm, Eu, Gd, Dy) has been performed. All materials crystallise in the cubic Fm (3) over barm symmetry space group and the cell volume decreases as RE varies from Sm to Dy in accordance with Vegard's law. An antiferromagnetic transition is observed below T-N = 130 and 112 K for RE = Sm and Eu, respectively. The Neel temperatures of these ordered rare earth molybdenum double perovskites are much higher than previously observed in double perovskites containing Eu or Sm and a 4d or 5d transition metal arranged in an ordered rock salt configuration. The high Neel temperatures arise due to a strong superexchange magnetic interaction via the Mo-O-RE-O-Mo pathway. All of the phases are electronically insulating and there is no evidence of magnetoresi stance at any temperature. (c) 2005 Elsevier Ltd. All rights reserved.
- double perovskite
- NEUTRON POWDER-DIFFRACTION