Polycrystalline La3Ni2O7-δ Superconductor

Tc up to 86.1 K

Inhomogeneity of oxygen content in the polycrystalline system more readily achieves the optimal oxygen stoichiometry for superconductivity, with a transition temperature exceeding parent single crystals.

Ke, Wang · Hou, Qiang · Yun-Qing, Shi · Zhang, Shengnan · Ziyu, Liang · Liu, Wenhui · Xin, Zhou · Wei, Wei · Ren, Zhi'an · Sheng, Li · Shi, Zhixiang

Journal of Alloys and Compounds 2026

Specifications

Superconducting transition temperature

{'zh': '86.1', 'en': '86.1'} K

Resistance drop temperature

{'zh': '80', 'en': '80'} K

Advantages

Tc surpasses parent single crystals

Inhomogeneity of oxygen content in the polycrystalline system makes it easier to achieve the optimal oxygen stoichiometry for superconductivity, leading to a higher transition temperature.

Superconducting transition under various pressures

Resistance drops around 80 K are observed in all samples under various pressures, indicating that superconductivity is robust against pressure variation, which is favorable for applications.

Empirical formula proposed for anomalous transition

An empirical formula is proposed to quantitatively analyze the anomalous superconducting transition in polycrystalline samples, which arises from the interplay between magnetoresistance contributions from superconducting and non-superconducting regions.

Applications

• High-temperature superconductors：Replacing cuprate high-temperature superconductors, exploring new superconducting systems above liquid nitrogen temperature
• Superconducting electronic devices：Fabricating superconducting films or devices with simpler processing and lower material cost
• High-pressure physical property measurement：Serving as a reference sample for high-pressure transport measurements to verify setup reliability and calibrate new pressure techniques
• Strongly correlated electron systems：Studying the interplay between pressure-induced superconductivity, magnetism, and localization in nickelates