On estimating superconducting shielding volume fraction from susceptibility in pressurized Ruddlesden-Popper nickelates: Response to arXiv:2602.19282

摘要

这篇回应性论文澄清了在加压Ruddlesden-Popper镍酸盐中超导屏蔽体积分数的评估方法。作者指出，他们的方法直接源于有限样品的标准静磁自洽关系（公式2-4），通过退磁因子N修正测量磁化率以得到内在磁化率，并由此估计屏蔽体积分数（f ≈ -χ）。该方法已在超导体文献中广泛应用数十年。以单晶样品S₆为例，在50 GPa和5 K下，应用自洽公式计算得到超导屏蔽体积分数约为86%，而在40 GPa下约为82%。作者论证，arXiv:2602.19282中质疑的根本缺陷在于对方假设测量到的抗磁矩与超导屏蔽体积分数成线性比例，并通过计算全屏蔽麦斯纳磁矩进行简单归一化。这一假设对于强退磁的薄圆盘状样品不成立，因为内场与磁化通过退磁场自洽耦合，使得测量磁矩与屏蔽分数呈非线性关系，从而导致对方方法给出约60%的偏低估计。论文还讨论了单退磁因子框架的适用范围，指出其样品结构均匀、质量高，支持该宏观描述，而对方构造的人为相分离模型不适用于此。作者结论认为，基于静磁自洽的方法是正确且广泛采用的标准方法。

材料

• La₄Ni₃O₁₀
• La₃Ni₂O₇
• La₂PrNi₂O₇

方法

• magnetostatic self-consistency
• demagnetization factor calculation
• SQUID magnetometry
• magnetic susceptibility measurement

关键词

• superconducting shielding volume fraction
• demagnetization factor
• meissner effect
• magnetostatic self consistency
• linear proportionality assumption flaw

亮点

• The assumption that the measured diamagnetic moment is linearly proportional to the superconducting shielding volume fraction is not valid for strongly demagnetized, thin disk-like specimens.
• The single-N framework is applicable for high-quality single crystals but not for phase-separated models with explicit inhomogeneities.
• The method based on magnetostatic self-consistency (Eqs. 2–4) is widely adopted in the superconductivity literature for decades.

结论

• The estimation of the superconducting shielding volume fraction in pressurized Ruddlesden–Popper nickelates is conducted within the well-established magnetostatic self-consistency framework, as outlined in Eqs. (2)–(4).
• This framework ensures that the demagnetization-corrected superconducting shielding volume fractions are consistent with long-standing experimental practices in the superconductivity community.
• The discrepancies claimed in Ref. [1] arise from a fundamental flaw in their methodology, particularly the assumption that the measured diamagnetic moment is linearly proportional to the superconducting shielding volume fraction in the presence of a finite demagnetization factor N.
• Therefore, our approach, grounded in magnetostatic self-consistency, remains the correct and widely accepted method for estimating superconducting shielding volume fractions.

主要论断

• The demagnetization-corrected superconducting shielding volume fraction follows the standard magnetostatic self-consistency relation, widely used in the literature for decades.
  • 证据: abstract states method follows from standard self-consistency and has been widely adopted,full_text provides detailed derivation and references 6-35
• The critique in arXiv:2602.19282 is flawed because it assumes linear proportionality between measured moment and shielding fraction, which is invalid for strongly demagnetized samples.
  • 证据: abstract: 'the discrepancies claimed in Ref. [1] stem from a fundamental flaw in their approach',full_text: 'the central flaw is that this normalization implicitly assumes linear scaling'
• For sample S₆ at 50 GPa, the self-consistent method yields a superconducting shielding volume fraction of ≈86%, while the alternative method underestimates it to ≈60%.
  • 证据: full_text provides explicit calculation: χ0 = -2.405, χ = -0.863, f ≈ 86%,summary_en states ≈86% at 50 GPa and ≈82% at 40 GPa

研究流程

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