Spin order and dynamics in the topological rare-earth germanide semimetals

• DOI: 10.48550/arxiv.2406.16425
• Publication Date: 2024-06-24
• Authors: Yuhao Wang; Zhixuan Zhen; Jing Meng; Igor V. Plokhikh; Delong Wu; D. J. Gawryluk; Yang Xu; Qingfeng Zhan; M. Shi; E. Pomjakushina; T. Shiroka; Tian Shang
• Keywords: Germanide

The $RE$Al(Si,Ge) ($RE$ = rare earth) family, known to break both the inversion- and time-reversal symmetries, represents one of most suitable platforms for investigating interplay between correlated-electron phenomena topologically nontrivial bands. Here, we report on systematic magnetic, transport, muon-spin rotation relaxation ($\mu$SR) measurements (Nd,Sm)AlGe single crystals, which exhibit antiferromagnetic (AFM) transitions at $T_\mathrm{N} 6.1$ 5.9 K, respectively. In addition, NdAlGe undergoes also an incommensurate-to-commensurate ferrimagnetic transition 4.5 K. Weak transverse-field $\mu$SR confirm AFM transitions, featuring a $\sim$90 % magnetic volume fraction. cases, zero-field (ZF) reveal more disordered internal field distribution in than SmAlGe, reflected larger transverse rate $\lambda^\mathrm{T}$ $T \ll T_\mathrm{N}$. This may be due complex structure NdAlGe, series metamagnetic external field, while SmAlGe shows only robust order. topological Hall effect (THE) appears first second $H \parallel c$, it is absent SmAlGe. Such THE likely attributed field-induced spin textures. longitudinal $\lambda^\mathrm{L}(T)$, diverges near order, followed by clear drop < magnetically ordered state, fluctuations are significantly stronger general, our longitudinal-field data indicate vigorous thus providing valuable insights into origin possible textures Weyl semimetals.