Marcano N, Gómez Sal J C, Espeso J I, De Teresa J M, Algarabel P A, Paulsen C, Iglesias J R
Departamento CITIMAC, Universidad de Cantabria, 39005 Santander, Spain.
Phys Rev Lett. 2007 Apr 20;98(16):166406. doi: 10.1103/PhysRevLett.98.166406.
We present evidence for the existence of magnetic clusters of approximately 20 A in the strongly correlated alloy system CeNi 1-x Cux (0.7<or=x<or=0.2) based on small angle neutron scattering experiments as well as the occurrence of staircaselike hysteresis cycles at very low temperature (100 mK). An unusual feature is the observation of long-range ferromagnetic order below the cluster-glass transition without any indication of a sharp transition at a Curie temperature. These observations strongly support a phenomenological model where a percolative process connects both magnetic states. The model can account for all the puzzling data previously obtained in this system, providing a new perspective with regard to the magnetic ground state of other alloyed compounds with small magnetic moments or weak ferromagnetism with intrinsic disorder effects.
基于小角中子散射实验以及在极低温（100 mK）下出现的阶梯状磁滞回线，我们给出了在强关联合金体系CeNi₁₋ₓCuₓ（0.2≤x≤0.7）中存在约20 Å磁团簇的证据。一个不寻常的特征是在团簇玻璃转变温度以下观察到长程铁磁有序，且没有任何在居里温度处出现尖锐转变的迹象。这些观察结果有力地支持了一个唯象模型，其中一个渗流过程连接了两种磁状态。该模型可以解释此前在这个体系中获得的所有令人困惑的数据，为其他具有小磁矩或具有内在无序效应的弱铁磁性合金化合物的磁基态提供了一个新视角。
