Oxide Superionic Conductivity of a-Axis-Oriented Ce0.75Sm0.25O2−δ Thin Film
© The Physical Society of Japan
This article is on
Oxide Superionic Conductivity of a-Axis-Oriented Ce0.75Sm0.25O2−δ Thin Film on Yttria-Stabilized Zirconia Substrate
(JPSJ Editors' Choice)
J. Phys. Soc. Jpn.
95,
014706
(2026)
.
Highly a-axis oriented Ce0.75Sm0.25O2-δ thin film fabricated on a yttria-stabilized zirconia substrate achieved oxide superionic conductivity, which can apply as an electrolyte in solid oxide fuel cells operating at medium temperature.
This research developed a strategy for fabricating ultrathin electrolyte layers of samarium-doped cerium oxide (SDC), which is known for its exceptional oxide-ion conductivity. The key innovation is the precise control of the structure of the material during the sputter deposition of the films. The SDC thin film with a thickness of 20 nm, fabricated on the yttria-stabilized zirconia (YSZ) single crystal, exhibited a high a-axis orientation. This highly controlled crystal orientation minimized the structural imperfections that reduce the high grain boundary resistance and limit the oxide-ion conductivity. The Cole–Cole plot obtained from the AC impedance spectra revealed a low bulk resistance of ~0.05 kW cm at 300 °C, with a low grain boundary resistance. The SDC thin film exhibited high surface oxide-ion conductivity (s > 10-2 S/cm) and an ionic transport number exceeding 90%, as confirmed by DC polarization measurements within the medium temperature range of 270–550 °C. This superior performance was attributed to (1) a large amount of oxygen vacancies (δ ≈ 0.17) formed on the surface of the b-c plane, (2) the suppression of electronic conductivity owing to a relatively large energy gap (~2.6 eV), and (3) strong Coulomb repulsion between 4f electrons. Through a series of experimental and analytical measurements of the thin-film electrolyte, the structurally ordered SDC thin film exhibited a world-record-high oxide-ion conductivity at temperatures ranging from 300 to 550 °C. Operating in this temperature range, rather than the standard SOFC operating range of 600–1,000 °C, can drastically improve the practicality and safety of fuel cell technology. Because it requires less heat, the system is less prone to material stress. This enables the use of less expensive components, accelerates cell start-up time, and increases overall energy efficiency.
(Written by Ryota Morizane on behalf of all authors.)
Oxide Superionic Conductivity of a-Axis-Oriented Ce0.75Sm0.25O2−δ Thin Film on Yttria-Stabilized Zirconia Substrate
(JPSJ Editors' Choice)
J. Phys. Soc. Jpn.
95,
014706
(2026)
.
Share this topic
Fields
Related Articles
-
Topological Photonics: Recent Advances in Controlling Light
Cross-disciplinary physics and related areas of science and technology
Dielectric, optical, and other properties in condensed matter
Electromagnetism, optics, acoustics, heat transfer, and classical and fluid mechanics
Electronic structure and electrical properties of surfaces and nanostructures
Structure and mechanical and thermal properties in condensed matter
2025-12-8
The special topics edition of the Journal of the Physical Society of Japan presents five new review articles offering cutting-edge information on the emerging field of topological photonics.
-
Superconducting Diode Using Semiconductor Quantum Dots
Electronic structure and electrical properties of surfaces and nanostructures
Superconductivity
2025-6-5
The superconducting diode effect is proposed for a three-terminal semiconductor double-quantum-dot device. This effect is considerably enhanced by the Dirac-point singularities in the superconducting phase space.
-
Higher-Order Topological Phases in Magnetic Materials with Breathing Pyrochlore Structures
Electronic structure and electrical properties of surfaces and nanostructures
Magnetic properties in condensed matter
Mathematical methods, classical and quantum physics, relativity, gravitation, numerical simulation, computational modeling
2025-4-7
A simple example of a higher-order topological phase, in which the symmetry decreases step-by-step from the bulk to the corner, is realized in a magnetic system with a pyrochlore structure and is characterized by a series of quantized Berry phases defined for the bulk, surface, and edge.
-
Shaping the Future of Materials Science with Tanabe–Sugano Diagrams
Dielectric, optical, and other properties in condensed matter
Electron states in condensed matter
Electronic structure and electrical properties of surfaces and nanostructures
Magnetic properties in condensed matter
2025-1-21
This special collection published in the Journal of the Physical Society of Japan celebrates 70 Years of Tanabe–Sugano Diagrams, highlighting their continued role in advancing materials with transition metals.
-
How to Construct a 3D Dirac Semimetal by Stacking 2D Massless Dirac Fermion Layers
Electron states in condensed matter
Electronic structure and electrical properties of surfaces and nanostructures
2025-1-14
Interlayer spin–orbit coupling originating from the anion potential gives rise to a 3D Dirac semimetal state that preserves inversion symmetry in the multilayer organic massless Dirac fermion system α-(ET)2I3.