Ni9Te6(PEt3)8C60 Is a Superatomic Superalkali Superparamagnetic Cluster Assembled Material (S3-CAM)

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• 作者：Vikas Chauhan ; Sanjubala Sahoo ; Shiv N. Khanna
• 刊名：Journal of the American Chemical Society
• 出版年：2016
• 出版时间：February 17, 2016
• 年：2016
• 卷：138
• 期：6
• 页码：1916-1921
• 全文大小：367K
• ISSN：1520-5126

文摘

First-principles theoretical studies enable an electronic and magnetic characterization of the recently synthesized Ni₉Te₆(PEt₃)₈C₆₀ ionic material consisting of Ni₉Te₆(PEt₃)₈ superatoms and C₆₀. The PEt₃ ligands are shown to create an internal coulomb well that lifts the quantum states of the Ni₉Te₆ cluster, lowering its ionization potential to 3.39 eV thus creating a superalkali motif. The metallic core has a spin magnetic moment of 5.3 μ_B in agreement with experiment. The clusters are marked by low magnetic anisotropy energy (MAE) of 2.72 meV and a larger intra-exchange coupling exceeding 0.2 eV, indicating that the observed paramagnetic behavior around 10K is due to superparamagnetic relaxations. The magnetic motifs separated by C₆₀ experience a weak superexchange that stabilizes a ferromagnetic ground state as observed around 2 K. The calculated MAE is sensitive to the charged state that could account for the observed change in magnetic transition temperature with size of the ligands or anion.