Instituto de Ciencia de Materiales de Aragón and Departamento de Física de la Materia Condensada, Universidad de Zaragoza-CSIC, Pedro Cerbuna 12, 50009 Zaragoza, Spain.
J Phys Condens Matter. 2011 Feb 2;23(4):046003. doi: 10.1088/0953-8984/23/4/046003. Epub 2011 Jan 12.
The evolution of the crystal structure and magnetic properties with Fe content in NdFe(x)Ga(1 - x)O(3) has been studied by magnetization, ac-susceptibility, x-ray and neutron scattering techniques for x ≥ 0.2 in order to determine the phase diagram of the series. X-ray diffraction shows that the crystallographic structure of NdFe(x)Ga(1 - x)O(3) can be described in the space group Pbnm for all x values. Both the magnetic ordering and spin reorientation temperatures of the Fe magnetic sublattice decrease with iron concentration due to the presence of magnetic vacancies occupied by Ga. The long-range Fe magnetic ordering disappears for x ≤ 0.3, while ac-susceptibility measurements evidence the presence of short-range Fe ordered clusters and superspin-glass-like effects for x well below the percolation threshold. The magnetic structure of the compounds, including the spin reorientation temperature range, is determined by high-resolution neutron diffraction analysis. Although the presence of finite magnetic clusters for x values close to percolation is evidenced, the study of a percolation quantum phase transition in this series is hindered by the presence of Nd magnetic moments and a sizeable distribution of composition Δx around the nominal value.
通过磁化、交流磁化率、X 射线和中子散射技术研究了 NdFe(x)Ga(1 - x)O(3)中 Fe 含量对晶体结构和磁性的影响，以确定该系列的相图。X 射线衍射表明，对于所有 x 值，NdFe(x)Ga(1 - x)O(3)的晶体结构可以用空间群 Pbnm 来描述。由于 Ga 占据了磁性空位，Fe 磁亚晶格的磁有序和自旋重定向温度都随铁浓度的增加而降低。对于 x≤0.3，长程 Fe 磁有序消失，而 ac 磁化率测量表明，在低于渗流阈值的 x 值下存在短程 Fe 有序簇和超自旋玻璃状效应。化合物的磁结构，包括自旋重定向温度范围，通过高分辨率中子衍射分析来确定。尽管在接近渗流值的 x 值处存在有限的磁性簇，但由于 Nd 磁矩的存在和组成 Δx 在标称值附近的大量分布，该系列的渗流量子相变研究受到阻碍。
