Long-period, longitudinal spin density modulation in an itinerant 5f magnetic compound UCu2Si2
Long-period, longitudinal spin density modulation in an itinerant 5f magnetic compound UCu2Si2
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DOI：
10.1088/0953-8984/18/2/010
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发表时间：
2006-01-18
影响因子：
2.7
通讯作者：
Onuki, Y
中科院分区：
文献类型：
--
作者：
Honda, F;Metoki, N;Onuki, Y
利用中子散射研究了UCu2Si2的磁结构。我们观察到 100 K < T < 106 K 的一阶和非常弱的三阶不通约卫星反射，传播 q = [0 0 delta]，T = 101 K 时 delta = 0.116，表明接近正弦磁调制，长周期为 Lambda = 85.7 埃。一阶卫星反射的强度与平行于c轴的力矩方向一致。由于晶格调制伴随着电荷密度波，二阶卫星无法在我们的实验灵敏度内检测到。 UCu2Si2 中的长周期磁调制无法用基于受挫反铁磁短程相互作用的 ANNNI 模型来解释。接近正弦的长周期调制是 UCu2Si2 中 5f 电子的巡回行为导致的自旋密度波状态的证据。铁磁基态和非公度相的非常弱的上临界场与长周期性一致。
The magnetic structure Of UCu2Si2 has been studied by means of neutron scattering. We have observed the first- and very weak third-order incommensurate satellite reflections for 100 K < T < 106 K with the propagation q = [0 0 delta], delta = 0.116 at T = 101 K, indicating nearly sinusoidal magnetic modulation with long periodicity of Lambda = 85.7 angstrom. The intensity of the first-order satellite reflections is consistent with a moment direction parallel to the c-axis. The second-order satellite due to lattice modulation accompanied by a charge density wave could not be detected within our experimental sensitivity. The long-period magnetic modulation in UCu2Si2 cannot be explained in terms of an ANNNI model based on frustrated antiferromagnetic short-range interactions. The nearly sinusoidal long-period modulation is evidence for a spin density wave state as a consequence of itinerant behaviour of the 5f electrons in UCu2Si2. The ferromagnetic ground state and the very weak upper critical field for the incommensurate phase are consistent with the long periodicity.