Low temperature neutron diffraction studies of Sr 2 FeMO 6 (M=Nb, Sb)

• DOI: 10.1007/s003390201362
• Publication Date: 2003-11-24T16:48:55Z
• Authors: N. Kashima; K. Inoue; T. Wada; Y. Yamaguchi
• Keywords: 02 engineering and technology; 0210 nano-technology

Crystal structures and magnetic properties of Sr2FeMO6 (M=Nb, Sb) were studied by X-ray and neutron diffraction. Sr2FeNbO6 and Sr2FeSbO6 showed a magnetic susceptibility maximum at 20 and 35.5 K, respectively. Above their magnetic transition temperatures, Sr2FeNbO6 had an orthorhombic unit cell with a space group of Pbnm and Sr2FeSbO6 had a monoclinic unit cell with a space group of P21/n. For Sr2FeNbO6, the six-coordinate site of perovskite structure was randomly occupied by Fe and Nb and, for Sr2FeSbO6, it was orderly occupied by Fe and Sb. The magnetic susceptibilities of Sr2FeNbO6 showed hysteresis between field cooled and zero-field cooled conditions below the transition of 20 K. The neutron diffraction pattern of Sr2FeNbO6 showed no evidence of a long range magnetic ordering at 2.3 K and that of Sr2FeSbO6 included some magnetic Bragg peaks. We conclude that Sr2FeNbO6 transforms to a spin glass state below 20 K, and Sr2FeSbO6 transforms to an anti-ferromagnetic state below 35.5 K.