Analyzing the enforcement of a high-spin ground state for a metallacrown single-molecule magnet

作者：Happ P; Sapozhnik A; Klanke J; Czaja P; Chernenkaya A; Medjanik K; Schuppler S; Nagel P; Merz M; Rentschler E; Elmers H J^*

来源：Physical Review B, 2016, 93(17): 174404.

DOI：10.1103/PhysRevB.93.174404

We have studied element-selective magnetic properties of the hetero-and homometallic metallacrowns Cu(II)(2)[12 - MCYN(Shi)-4] (Y = Cu, Fe, in short CuCu4 and CuFe4). These metallacrowns comprise four Fe or Cu ions surrounding a central Cu ion. Using x-ray magnetic circular dichroism we have probed local symmetries, electronic configuration, orbital and spin magnetic moments of the magnetic ions. The ratio between the Cu and Fe moment of -0.11 is independent of temperature in the range of 15 K to 90 K. The Cu moment shows antiparallel to the Fe moment. For CuCu4 we confirm the predicted S = 1/2 ground state. The comparison of the spectral dependence indicates a localization of the magnetic moment at the central Cu ion. The orbital to spin moment ratio is 0.03 for the Fe ion while a larger ratio of 0.12 was measured for the Cu ion in both compounds. The experimental results are compared to a mean field model and to an isotropic Heisenberg model.

• 出版日期2016-5-3