Structure and magnetism in Pr3RuO7.
INT J INORG MATER
53 - 59.
The crystal structure of the ordered fluorite, Pr3RuO7, was refined from powder neutron diffraction data in Cmcm. An interesting structural feature is the presence of relatively well separated zig-zag chains of corner sharing RuO6 octahedra, Ru-Ru interchain distance 0.61 Angstrom vs. Ru-Ru intrachain distance of 3.76 Angstrom. Magnetic susceptibility data show a Curie-Weiss behavior for T>225 K with C=5.96(4) emu K mol(-1) and theta(c)=+11(2) K. In an attempt to separate the contributions of Pr(3+) and Ru(5+), the properties of isostructural Pr3TaO7 were also measured, yielding C=4.63(3) emu K mol(-1). Thus, the contribution of Ru(5+), 4d(3), S=3/2, to the measured Curie constant is estimated to he 1.33 emu K mol(-1), not far from the spin-only value of 1.87 emu K mol(-1). This supports the view that the Ru 4d elections are localized acid magnetic, not itinerant. A susceptibility maximum at about 50 K is attributed to long-range magnetic order and this is substantiated by neutron diffraction data. There is little evidence for one-dimensional antiferromagnetic correlations in this material but behavior characteristic of short-range ferromagnetic correlations attributed to Pr-Ru exchange interactions are found in the temperature range 50-200 K, consistent with the positive theta(c). (C) 2000 Elsevier Science Ltd. All rights reserved.
|Title:||Structure and magnetism in Pr3RuO7|
|Keywords:||oxides, chemical synthesis, neutron scattering, X-ray diffraction, magnetic properties, M = NB, RARE-EARTH, SB, TA, SC|
|UCL classification:||UCL > School of BEAMS > Faculty of Maths and Physical Sciences > Chemistry|
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