Joint Workshop LANL/NIMS Quantum and Functional Materials and MANA International Symposium 2024

Quantum Materials - 03

Title

Phase diagram exploration of pressure-induced superconductor La3Ni2O7+δ

Author's photo

Authors

Yuta Ueki, Hiroya Sakurai1, Hibiki Nagata1,2, Kazuki Yamane1,2,
Ryo Matsumoto1, Kensei Terashima1, Keisuke Hirose3,
Hiroto Ohta3, Masaki Kato3, Yoshihiko Takano1,2

Affiliations

1. Frontier Superconducting Materials Group, MANA, NIMS
2. Graduate School of Pure and Applied Sciences, University of Tsukuba
3. Faculty of Science and engineering, Doshisha University

URL

https://www.nims.go.jp/NFM/

Email

UEKI.Yuta@nims.go.jp

Abstract

Recently, La₃Ni₂O₇ was found to exhibit superconducting transitions at pressures above 14 GPa, with transition temperature (Tc) of 80 K [1]. The crystal structure of this material is similar to high-Tc cuprates. However, while cuprates have 9 3d electrons, La₃Ni₂O₇ has 7.5 3d electrons. This difference suggests a different superconducting mechanism. The effect of oxygen nonstoichiometric on La₃Ni₂O₇ has not been extensively studied, but high-Tc cuprates is sensitive to oxygen content. Therefore, this study aims to establish phase diagram of La₃Ni₂O₇, including temperature, pressure, and oxygen content. For the experimental method, we prepared La₃Ni₂O₇+δ with various oxygen content by applying different annealing and performed electrical resistance measurements under high pressure using diamond anvil cell with boron-doped diamond electrodes, as shown in Fig. 1[2]. Based on the results, we established the T—δ phase diagram shown in Fig. 2. Broad range of phases from insulator to superconductor depending on the oxygen content, the pressure dependence of Tc also varies.

Fig. 1. Structure of Diamond Anvil Cell
Fig. 2. Phase diagram of La₃Ni₂O₇+δ

Reference

  1. H. Sun, M. Hou, X. Hu, J. Li, Z. Liu, Y. Han, L. Tang, Z. Mao, P. Yang, B. Wang, J. Cheng, D.-X. Yao, G.-M. Zhang, and M. Wang, Nature 621, 493, (2023).
  2. Y. Sasama, M. Fujioka, T. Irifune, M. Tanaka, T. Yamaguchi, H. Takeya, and Y. Takano, et al., Rev. Sci. Instrum. 87, 076103 (2016). DOI 10.1063/1.4959154