Spin fluctuations in both the ordered and paramagnetic phases of MnSi! MnSi a heavy Fermi liquid?
Spin fluctuations in both the ordered and paramagnetic phases of MnSi! MnSi a heavy Fermi liquid?
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MnSi 有序相和顺磁相中的自旋涨落！
DOI：
10.1007/bf01420586
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发表时间：
1982
期刊：
影响因子：
--
通讯作者：
J. Booth
中科院分区：
文献类型：
--
作者：
K. Ziebeck;H. Capellmann;P. Brown;J. Booth
极化中子和极化分析已被用来确定漫磁散射MnSi作为温度的函数。在50 K（1.72 Tc）和100 K（3.45 Tc）的顺磁相测量证实了先前在300 K（10 Tc）和580 K（20 Tc）报道的强空间相关性的存在。自旋密度区域之间的空间相关性由120 μ m分隔，具有铁磁性质，并决定了静态磁化率。在反原子体积上的顺磁响应的积分得到了每个锰原子的磁矩为1.2μB，这个值比在4.2 K下布拉格散射和磁化测量中观察到的0.4 μ B大得多。在11K下对有序磁相进行的测量显示出很强的漫散射，对应于每个Mn原子10.8 μ B。在顺磁相中观察到的漫散射的增加对应于布拉格分量进入background.The存在下，在有序相和非常不寻常的波矢依赖性的漫散射观察到在11 K的显着的散射已被解释假设MnSi是一个沉重的费米液体。此外，我们相信这些测量给出了交换孔的第一次直接观察。
Polarised neutrons and polarisation analysis have been used to determine the diffuse magnetic scattering from MnSi as a function of temperature. Measurements at 50 K (1.72Tc) and 100 K (3.45Tc) in the paramagnetic phase confirmed the presence of strong spatial correlations previously reported at 300 K (10Tc) and 580 K (20Tc). The spatial correlations between regions of spin density separated by ∼ 12 Å are of a ferromagnetic nature and determine the static susceptibility. Integration of the paramagnetic response over an inverse atomic volume yields a moment per manganese atom of ∼1.2μB, a value considerably larger than the 0.4 μBobserved in Bragg scattering and magnetisation measurements at 4.2 K. Measurements made at 11 K in the ordered magnetic phase reveal strong diffuse scattering corresponding to ∼0.8 μBper Mn atom. The increase in the diffuse scattering observed in the paramagnetic phase corresponds to the passage of the Bragg component into the background.The presence of significant scattering in the ordered phase and the very unusual wave vector dependence of the diffuse scattering observed at 11 K has been interpreted assuming MnSi to be a heavy Fermi liquid. Furthermore we believe these measurements give the first direct observation of the exchange hole.