High-pressure scheelite-type polymorph of SmCrO4: synthesis, structural characterization and magnetic properties
来源期刊：JOURNAL OF RARE EARTHS2010年第6期
论文作者：Regino Sáez-Puche Mahmoud Gamal Rabie Julio Romero de Paz José-Manuel Gallardo-Amores Esteban Climent Pascual
文章页码：936 - 939
摘 要：The new scheelite form of SmCrO4 oxide was obtained by heating the zircon-type SmCrO4 oxide at 4 GPa and 803 K. X-ray diffraction revealed that this scheelite SmCrO4 phase crystallized with tetragonal symmetry, S.G. I41/a and lattice parameters: a=0.50776（3） nm and c=1.15606（2） nm. This structural phase transition from zircon to scheelite involved a decreasing of around 10% in the unit cell volume. Although the Cr-O and Sm-O distances did not change very much in both zircon and scheelite polymorphs, the changes occurred in the bond angles were remarkable that appear to support the proposed reconstructive model to explain this structural zircon-scheelite phase transition. Magnetic susceptibility and magnetization measurements revealed that the scheelite SmCrO4 oxide behaved an antiferromagnetic material, where the Sm3+ and Cr5+ were simultaneously ordered. The estimated Néel temperature, TN, was 16 K and the critical field at 12 K associated with the metamagnetic transition was 3.2 T.
Regino Sáez-Puche，Mahmoud Gamal Rabie，Julio Romero de Paz，José-Manuel Gallardo-Amores，Esteban Climent Pascual
Department of Inorganic Chemistry, Faculty of Chemical Sciences, Complutense University of Madrid, Ciudad Universitaria
摘 要：The new scheelite form of SmCrO4 oxide was obtained by heating the zircon-type SmCrO4 oxide at 4 GPa and 803 K. X-ray diffraction revealed that this scheelite SmCrO4 phase crystallized with tetragonal symmetry, S.G. I41/a and lattice parameters: a=0.50776（3） nm and c=1.15606（2） nm. This structural phase transition from zircon to scheelite involved a decreasing of around 10% in the unit cell volume. Although the Cr-O and Sm-O distances did not change very much in both zircon and scheelite polymorphs, the changes occurred in the bond angles were remarkable that appear to support the proposed reconstructive model to explain this structural zircon-scheelite phase transition. Magnetic susceptibility and magnetization measurements revealed that the scheelite SmCrO4 oxide behaved an antiferromagnetic material, where the Sm3+ and Cr5+ were simultaneously ordered. The estimated Néel temperature, TN, was 16 K and the critical field at 12 K associated with the metamagnetic transition was 3.2 T.
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