Abstract Body

Layered perovskite nickelate superconductor La3Ni2O7 (Tc~80K) under high pressure attract much attention due to similarity of crystal structure to high-Tc cuprate. And its superconductivity with high transition temperature (Tc) has been predicted to be unconventional pairing mechanism [1,2]. La₃Ni₂O₇ corresponds to the n = 2 case of the Ruddlesden-Popper phase represented by the general formula of La_n+1Ni_nO3_n+1, and it has two layers of NiO₂ plane. Particularly, La₄Ni₃O₁₀, is corresponding to n = 3 case of the Ruddlesden-Popper phase having triple layers of NiO₂ plane. Due to the similarity between these materials, we expect the possibility of superconductivity in La₄Ni₃O₁₀ under high pressure [3]. We synthesized polycrystalline samples of La₃Ni₂O₇ and La₄Ni₃O₁₀ and measure the temperature dependence of resistance under high pressure. Then we have successfully discovered new superconductor La₄Ni₃O₁₀ under high pressure [4-6].

Transition temperature of high-Tc cuprate is strongly related to carrier density that depends on oxygen content. The same properties are expected also in nickelate superconductors. We have synthesized La₃Ni₂O₇ and La₄Ni₃O₁₀ samples with different oxygen contents and perform resistivity measurements under high pressure. Particularly, La₄Ni₃O₁₀, shows strong oxygen contents dependence of transition temperature, and Tc exceed 36K at 48GPa which is the highest in this system [5]. In my presentation I will talk about detailed superconducting properties.

References

[1] H. Sun et al., Nature 621, 493 (2023).

[2] M. Nakata et al., Phys. Rev. B 95, 214509 (2017).

[3] R. Matsumoto et al., Rev. Sci. Instrum. 87, 076103 (2016).

[4] H. Sakakibara et al., arXiv: 2309.09462. Phys. Rev. B 109, 144511 (2024)

[5] H. Nagata et al., arXiv: 2405.19880.

[6] Y. Ueki et al., arXiv: 2408.04970

Keywords: Superconductivity, Nickelate, High Pressure, Perovskite