Evolution of superconductivity evidence in pressurized La3−xSmxNi2O7

Qingyi Zhong; Junfeng Chen; Zhengyang Qiu; Jingyuan Li; Xing Huang; Peiyue Ma; Mengwu Huo; Hongliang Dong; Sihao Deng; Lunhua He; Yifeng Han; Hualei Sun; Meng Wang

doi:10.1103/pzv7-1nlr

Evolution of superconductivity evidence in pressurized La3−xSmxNi2O7

Qingyi Zhong, Junfeng Chen, Zhengyang Qiu, Jingyuan Li, Xing Huang, Peiyue Ma, Mengwu Huo, Hongliang Dong, Sihao Deng, Lunhua He, Yifeng Han, Hualei Sun, Meng Wang

DOI 10.1103/pzv7-1nlr · Physical Review B

T1

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Abstract

Motivated by the discovery of superconductivity in bilayer La3Ni2O7 at 80 K and the increased superconducting transition temperature, Tc, up to 96 K in single crystals of La1.57Sm1.43Ni2O7−δ under pressure, we systematically study the effect of Sm substitution on the superconductivity and structure of La3−xSmxNi2O7 (0≤x≤1.5) under pressure. Experimental investigations in polycrystalline samples reveal that Sm substitution monotonically decreases the lattice constants c and a, thereby enhancing crystal structural distortion and leading to an evolution of the metallic ground state in La3Ni2O7 to an insulating state in La1.5Sm1.5Ni2O7. The optimal Tconset rises with increasing Sm substitution, and the maximum Tconset is 89.2 K in polycrystalline La1.5Sm1.5Ni2O7. Divergences in Tc compared with single crystals of La1.57Sm1.43Ni2O7−δ are likely due to variations in the microstructure induced by different material growth approaches. Our results suggest that the enhancement of Tc in La3−xSmxNi2O7 is mainly affected by the compressed c lattice before saturation, and the superconducting transition pressure increases with substitution concentration. Our experimental results provide insight into the influence of small-radius rare-earth element substitution on nickelate superconductors, offering a means to further increase the transition temperature.

Source-reported materials — not catalogue approval

Formula	Reported Tc (K)	Pressure (GPa)	Type
La3Ni2O7 Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	80	Pressure not reported	onset
La1.57Sm1.43Ni2O7-δ Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	96	21.6 GPa	onset
La1.5Sm1.5Ni2O7 Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	89.2	37.1 GPa	onset
La3Ni2O7 Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	83	18 GPa	onset
La2PrNi2O7 Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	82.5	16 GPa	onset
La2.1Nd0.9Ni2O7 Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	80	22.8 GPa	onset
La2.7Sm0.3Ni2O7 Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	77.5	Pressure not reported	onset
La2.4Sm0.6Ni2O7 Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	81	Pressure not reported	onset
La2.1Sm0.9Ni2O7 Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	88.7	30.3 GPa	onset