Muyuan Zou | Searcharxiv

arXiv2024

Evidence of spin density waves in La$_3$Ni$_2$O$_{7-δ}$

The recently discovered superconductivity with critical temperature $T_c$ up to 80 K in the double-layer Nickelate La$_3$Ni$_2$O$_{7-δ}$ under pressure has drawn great attention. Here we report the positive muon spin relaxation ($μ^+$SR) study of polycrystalline La$_3$Ni$_2$O$_{6.92}$ under ambient pressure. Zero-field $μ^+$SR experiments reveal the existence of magnetic order in La$_3$Ni$_2$O$_{6.92}$ with $T_{N}=154\ \rm{K}$. The weak transverse field $μ^+$SR measurements confirms the bulk nature of magnetism. In addition, a small quantity of oxygen deficiencies can greatly broaden the internal magnetic field distribution sensed by muons.

cond-mat.str-el↗

arXiv2020

Evidence the ferromagnetic order on CoSb layer of LaCoSb$_2$

The emergence of unconventional superconductivity is generally considered to be related to spin fluctuations. Unveiling the intriguing behaviors of spin fluctuations in parent compounds with layered transition-metal ions may shed light on the search for exotic unconventional superconductors. Here, based on the framework of the first-principles calculations, we theoretically propose that LaCoSb$_2$ is a weak antiferromagnetic layered metal with an in-plane ferromagnetic moment of 0.88 $μ_B$ at the Co sites, as a candidate parent compound of the cobalt-based superconductors. Importantly, this theoretical finding is experimentally supported by our magnetization measurements on polycrystalline samples of LaCo$_{0.78}$Sb$_2$. Following the symmetry analysis, we suggest a possible $p$-wave superconductivity hosted in doped LaCoSb$_2$ emerging at the verge of ferromagnetic spin fluctuations, which implies potential applications in topological quantum computing in future.

cond-mat.supr-con↗