Exploration of Superconductivity in Layered Perovskite Nickelate La₄Ni₃O₁₀ under High Pressure

Recent discovery of superconductivity in layered perovskite nickelate La₃Ni₂O₇ (Tc~80K) attract much attention due to its high superconducting transition temperature (Tc) and similarity of crystal structure to high-Tc cuprate [1]. And its mechanism of superconductivity is expected to be unconventional [2]. La₃Ni₂O₇ corresponds to the n = 2 case of the Ruddlesden-Popper phase represented by the general formula of La_n+1Ni_nO_3n+1, and it has two layers of NiO₂ plane. In general, Ruddlesden-Popper phase has two-dimensional crystal and electric structure which is suitable for appearance of superconductivity for instance KCa₂Nb₃O₁₀ [3]. Particularly, La₄Ni₃O₁₀, is corresponding to n = 3 case of the Ruddlesden-Popper phase having three layers of NiO₂ plane. Due to the similarity between these materials, we expect the possibility of superconductivity in La₄Ni₃O₁₀ under high pressure [4].<br/>We synthesized polycrystalline samples, La₃Ni₂O₇ and La₄Ni₃O₁₀, via solid-phase reaction and Hot Isostatic Pressing process from La₂O₃and NiO [4]. Samples are characterized by powder X-ray diffraction and thermogravimetry. High pressure was generated with Diamond Anvil Cell with boron-doped diamond electrodes designed for four-terminal resistance measurement [5]. Cubic boron nitride powder was used as a pressure-transmitting medium.<br/>La₄Ni₃O₁₀ displays metallic behavior across all measured pressures, with a slight upturn observed at temperatures below approximately 100 K. At 32.8 GPa, a drop in resistance suddenly appears below 5 K. With increasing the pressure beyond 46.2 GPa, the drop of resistance becomes significant. And the temperature where the resistance begins to drop elevated up to 23K at 79.2 GPa. Magnetic field dependence of resistance was measured at 69.4 GPa. As the magnetic field increases, the drop of resistance becomes smaller. Therefore, the drop in resistance is most likely to be the result of a superconducting transition of La₄Ni₃O₁₀ [4].<br/><br/>References:<br/>[1] H. Sun et al., Nature 621, 493 (2023).<br/>[2] M. Nakata et al., Phys. Rev. B 95, 214509 (2017).<br/>[3] Y. Takano et al., Solid State Commun., 103, 215 (1997).<br/>[4] H. Sakakibara et al., arXiv: 2309.09462.<br/>[5] R. Matsumoto et al., Rev. Sci. Instrum. 87, 076103 (2016).