The influence of magnetic sublattice dilution on magnetic order in CeNiGe3 and UNiSi2
Adam P. Pikul
备注：
This is an author-created, un-copyedited version of an article accepted for publication in Journal of Physics: Condensed Matter. IOP Publishing Ltd is not responsible for any errors or omissions in this version of the manuscript or any version derived from it. The definitive publisher-authenticated version is available online at doi:10.1088/0953-8984/24/27/276003
Polycrystalline samples of the Y-diluted antiferromagnet CeNiGe3 (T_N = 5.5 K) and Th-diluted ferromagnet UNiSi2 (T_C = 95 K) were studied by means of x-ray powder diffraction, magnetization and specific heat measurements performed in a wide temperature range. The lattice parameters of the Ce1-xYxNiGe3 alloys decrease linearly with increasing the Y content, while the unit cell volume of U1-xThxNiSi2 increases linearly with rising the Th content. The ordering temperatures of the systems decrease monotonically with increasing x down to about 1.2 K in Ce0.4Y0.6NiGe3 and 26 K in U0.3Th0.7NiSi2, forming a dome of a long-range magnetic order on their magnetic phase diagrams. The suppression of the magnetic order is associated with distinct broadening of the anomalies at T_N,C due to crystallographic disorder being a consequence of the alloying. Below the magnetic percolation threshold xc of about 0.68 and 0.75 in the Ce- and U-based alloys, respectively, the long-range magnetic order smoothly evolves into a short-range one, forming a tail on the magnetic phase diagrams. The observed behaviour Ce1-xYxNiGe3 and U1-xThxNiSi2 is characteristic of diluted magnetic alloys. (c) 2012 IOP Publishing Ltd.
Spin reorientation of the Fe moments in Eu$_{0.5}$Ca$_{0.5}$Fe$_{2}$As$_{2}$: Evidence for a strong interplay of Eu and Fe magnetism
用互补极化和非极化单晶中子衍射方法研究了Eu $_{0.5}$ Ca $_{0.5}$ Fe $_{2}$ As $_{2}$的温度相关磁性结构。在A型反铁磁（AFM）结构中，当Eu位被等价的Ca $^{2+}$稀释50%时，在低于$\mathit{T_{Eu}}$ = 10 K的温度下，Eu亚晶格仍然是长程有序的.在2.5 K时，Eu $^{2+}$自旋的磁矩大小为6.74（4）$μ_{B}$. Fe亚晶格在$\mathit{T_{SDW}}$ = 192（2）K时经历自旋密度波转变，并在$\mathit{T_{Eu}}$上方显示面内AFM结构。而在2.5 K时，Fe的$^{2+}$矩在与$\mathit{ab}$平面成14（4）°的倾斜AFM结构中是有序的.低于Eu的AFM有序温度的Fe的自旋重取向提供了Eu $_{0.5}$ Ca $_{0.5}$ Fe $_{2}$ As $_{2}$中两个磁性亚晶格之间强相互作用的直接证据。
Frustration-driven topological textures on the honeycomb lattice: antiferromagnetic meron-antimeron and skyrmion crystals emerging from spiral spin liquids
