来源 自动抓取、Zotero
作者 Peiyue Ma, Jingyuan Li, Xing Huang, Yixing Zhao, Yifeng Han, Mengwu Huo, Deyuan Hu, Chaoxin Huang, Hengyuan Zhang, Sihao Deng, Lunhua He, Juan Rodriguez-Carvajal, Abhisek Bandyopadhyay, Alessandro Puri, Devashibhai Adroja, Xiang Chen, Tao Xie, Zhen Chen, Hualei Sun, Meng Wang
arXiv / 出版方 https://arxiv.org/abs/2605.04562
PDF https://arxiv.org/pdf/2605.04562
相关度评分 5.642
主分类 cond-mat.supr-con
发布日期 2026-05-07
研究范式 实验研究
样品形态 未知

摘要

本研究通过系统调控La3Ni2O7+δ系列样品的氧含量，合成了不同相组成的材料，包括纯双层相、双层与单层-双层杂化相混合相以及含三层交生的主双层相。高压输运测量表明，这些相分别对应不同的超导转变温度（T_c），其中双层相呈现约80 K的超导电性，杂化相和三层交生相的T_c较低。氧含量不仅影响相纯度，还直接调控双层超导电性的上临界场（H_c2），纯双层相具有更高的H_c2。通过建立T_c和H_c2随氧含量变化的相图，本研究实现了对Ruddlesden-Popper镍酸盐氧含量的精确控制，为理解其高压超导机制提供了关键实验依据。

材料

方法

关键词

亮点

  • Establishes a phase diagram of Tc and Hc2 as functions of oxygen content in La3Ni2O7+δ.

结论

  • Oxygen content governs phase purity, controlling the presence of hybrid phases and trilayer intergrowths.
  • Superconducting transitions with contrasting Tc values correspond to different phase fractions.
  • The upper critical field (Hc2) of the bilayer phase is directly modulated by oxygen content.

主要论断

  • Oxygen content in La3Ni2O7+δ controls the formation of intergrowth phases: low oxygen promotes hybrid-1212, high oxygen promotes trilayer inclusions.
    • 证据: NPD and STEM show hybrid-1212 phase in oxygen-deficient sample (δ=-0.14); trilayer intergrowths in oxygen-rich samples (δ>0)
  • Different RP phases show distinct superconducting transition temperatures: bilayer ≈80 K, hybrid-1212 ≈70 K, trilayer ≈4-6 K.
    • 证据: High-pressure transport at 25.5 GPa shows multiple transitions with these T_c values
  • The upper critical field H_c2 of the bilayer superconductivity is strongly modulated by oxygen content, peaking near stoichiometric composition.
    • 证据: Ginzburg-Landau fitting of transport under field shows that H_c2 increases with oxygen content up to δ=0, then decreases for higher δ

研究流程

  • sample_synthesis — Systematic control of oxygen content in La3Ni2O7+δ.
    • 材料: La2O3; NiO; Ni(NO3)2·6H2O
    • 方法: solid-state reaction; sol-gel method; controlled annealing in H2/N2, O2, and high-pressure O2
    • 观察: six samples with oxygen content δ from -0.34 to 0.08
  • structural_and_compositional_analysis — Oxygen content governs NiO6 tilting and formation of intergrowth phases.
    • 材料: polycrystalline La3Ni2O7+δ
    • 方法: XAFS; NPD; SXRD; STEM; TGA
    • 观察: oxygen content correlates with Ni valence and octahedral distortion; intergrowth phases identified
  • high_pressure_electronic_transport — Different RP phases exhibit distinct T_c values under pressure.
    • 材料: polycrystalline samples in DAC
    • 方法: four-probe resistivity measurement under pressure with KBr pressure medium
    • 观察: superconducting transitions with onset T_c ≈80 K for bilayer, ≈70 K for hybrid-1212, ≈5 K for trilayer
  • upper_critical_field_analysis — Oxygen content directly modulates H_c2 of bilayer superconductivity.
    • 材料: transport data at 25.5 GPa
    • 方法: Ginzburg-Landau fitting
    • 观察: H_c2 is modulated by oxygen content, peaking near stoichiometric composition