Yavors'kii Taras, Fennell Tom, Gingras Michel J P, Bramwell Steven T
Department of Physics and Astronomy, University of Waterloo, Ontario, N2L 3G1, Canada.
Phys Rev Lett. 2008 Jul 18;101(3):037204. doi: 10.1103/PhysRevLett.101.037204. Epub 2008 Jul 16.
Dy2Ti2O7 is a geometrically frustrated magnetic material with a strongly correlated spin ice regime that extends from 1 K down to as low as 60 mK. The diffuse elastic neutron scattering intensities in the spin ice regime can be remarkably well described by a phenomenological model of weakly interacting hexagonal spin clusters, as invoked in other geometrically frustrated magnets. We present a highly refined microscopic theory of Dy2Ti2O7 that includes long-range dipolar and exchange interactions to third nearest neighbors and which demonstrates that the clusters are purely fictitious in this material. The seeming emergence of composite spin clusters and their associated scattering pattern is instead an indicator of fine-tuning of ancillary correlations within a strongly correlated state.
Dy2Ti2O7是一种几何阻挫磁性材料，具有从1 K延伸至低至60 mK的强关联自旋冰态。在自旋冰态下的漫散射弹性中子散射强度可以通过弱相互作用六角形自旋簇的唯象模型得到非常好的描述，这一模型也被用于其他几何阻挫磁体。我们提出了一种高度精细的Dy2Ti2O7微观理论，该理论包括到第三近邻的长程偶极相互作用和交换相互作用，并且证明了在这种材料中簇是完全虚构的。相反，复合自旋簇及其相关散射图案的表面出现是强关联态内辅助关联微调的一个指标。
