Competing spin phases in geometrically frustrated magnetic molecules -: art. no. 017205
Competing spin phases in geometrically frustrated magnetic molecules -: art. no. 017205
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DOI：
10.1103/physrevlett.94.017205
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发表时间：
2005-01-14
影响因子：
8.6
通讯作者：
Kögerler, P
中科院分区：
文献类型：
--
作者：
Schröder, C;Nojiri, H;Kögerler, P
我们确定了一类零维的经典和量子海森堡自旋系统表现出异常的行为，在外部磁场B类似的几何受挫kagome晶格的经典自旋。我们对各向同性海森堡模型的计算表明，当温度T从0 K升高时，基于角共享三角形的结构，特别是八面体，立方八面体和二十面体的微分磁化率dM/dB在B-sat/3处出现明显的最小值。作为第一个实验证据，我们注意到巨大的Keplerate磁性分子{Mo 72 Fe 30}（二十面体的30个顶点上的Fe 3+离子）表现出这种行为。对于低T，当B近似于B（sat）/3时，存在两个竞争的自旋构型族，其中一个表现为磁“刚性”，导致dM/dB的减少。
We identify a class of zero-dimensional classical and quantum Heisenberg spin systems exhibiting anomalous behavior in an external magnetic field B similar to that found for the geometrically frustrated kagome lattice of classical spins. Our calculations for the isotropic Heisenberg model show the emergence of a pronounced minimum in the differential susceptibility dM/dB at B-sat/3 as the temperature T is raised from 0 K for structures based on corner-sharing triangles, specifically the octahedron, cuboctahedron, and icosidodecahedron. As the first experimental evidence we note that the giant Keplerate magnetic molecule {Mo72Fe30} (Fe3+ ions on the 30 vertices of an icosidodecahedron) exhibits this behavior. For low T when Bapproximate toB(sat)/3 two competing families of spin configurations exist of which one behaves magnetically "stiff" leading to a reduction of dM/dB.