Golubev Aleksandr, Dinnebier Robert E, Schulz Armin, Kremer Reinhard K, Langbein Hubert, Senyshyn Anatoliy, Law Joseph M, Hansen Thomas C, Koo Hyun-Joo, Whangbo Myung-Hwan
Max Planck Institute for Solid State Research , Heisenbergstrasse 1, D-70569 Stuttgart, Germany.
Institut für Anorganische Chemie der Technischen, Universität Dresden , Mommsenstr. 13, D-01062 Dresden, Germany.
Inorg Chem. 2017 Jun 5;56(11):6318-6329. doi: 10.1021/acs.inorgchem.7b00421. Epub 2017 May 8.
We prepared trirutile-type polycrystalline samples of CuTaO by low-temperature decomposition of a Cu-Ta-oxalate precursor. Diffraction studies at room temperature identified a slight monoclinic distortion of the hitherto surmised tetragonal trirutile crystal structure. Detailed high-temperature X-ray and neutron powder diffraction investigations as well as Raman scattering spectroscopy revealed a structural phase transition at 503(3) K from the monoclinic structure to the tetragonal trirutile structure. GGA+U density functional calculations of the spin-exchange parameters as well as magnetic susceptibility and isothermal magnetization measurements reveal that CuTaO is a new 1D Heisenberg magnet with predominant anti-ferromagnetic nearest-neighbor intrachain spin-exchange interaction of ∼50 K. Interchain exchange is a factor of ∼5 smaller. Heat capacity and low-temperature high-intensity neutron powder diffraction studies could not detect long-range order down to 0.45 K.
我们通过低温分解铜 - 钽 - 草酸盐前驱体制备了三氧化二铜型多晶样品CuTaO。室温下的衍射研究确定了迄今为止推测的四方三氧化二铜晶体结构存在轻微的单斜畸变。详细的高温X射线和中子粉末衍射研究以及拉曼散射光谱表明，在503(3) K时发生了从单斜结构到四方三氧化二铜结构的结构相变。自旋交换参数的GGA + U密度泛函计算以及磁化率和等温磁化测量表明，CuTaO是一种新型的一维海森堡磁体，具有约50 K的主要反铁磁最近邻链内自旋交换相互作用。链间交换约小5倍。热容量和低温高强度中子粉末衍射研究在低至0.45 K时未检测到长程有序。
