Group members

Abstract

Understanding the “structure-property relationship”, where the changes in crystal structure yield variations in physical properties, is an important issue in materials science. In particular, rare-earth based materials exhibit a wide variety of strongly-correlated phenomena, such as superconductivity and magnetism, and elucidating the role of 4f electrons remains a longstanding and important challenges. In this project, we focus on structural phase transition in rare-earth materials and aim to achieve a unified understanding of the accompanying changes in physical properties through experimental and computational approaches. Specifically, we study:

1. Structural phase transition of ternary compounds RTX with rare-earth elements (R), transition metals (T), and p-block elements (X);
2. Amorphous-amorphous transition in rare-earth alloys; and
3. Structural phase transitions of rare-earth materials in the monolayer limit.

Through these studies, we reveal the microscopic mechanism underlying the structural phase transition, with particular emphasis on the role of 4f electrons.

Group members

Abstract

Hydrogen is a promising energy carrier for realizing a sustainable and carbon-free society. Among various hydrogen storage technologies, hydrogen storage alloys are attractive due to their high volumetric hydrogen density and safe operability near ambient pressure. Magnesium (Mg) is a particularly attractive candidate owing to its high hydrogen storage capacity. However, its practical application is limited by slow reaction kinetics and the high thermal stability of its hydride. Our previous studies have demonstrated that alloying Mg with rare earth (RE) elements — known for their high affinity and reactivity with hydrogen — can significantly improve hydrogen absorption characteristics. Nevertheless, their hydrides still exhibit excessive thermodynamic stability, hindering reversible hydrogen release under ambient conditions. This task aims to design and develop RE-containing Mg-based hydrogen storage alloys with optimized compositions to achieve both high capacity and enhanced hydrogen desorption properties. By systematically tuning the RE-to-Mg ratio and incorporating additional alloying elements, we seek to enable reversible hydrogen storage near room temperature, thereby contributing to the practical deployment of hydrogen energy systems.

Group members

Abstract

The Hokkaido region is considered to have a relatively small-scale chemical and materials industry compared with other regions in Japan. In addition, the increase in waste generated through social and economic activities is expected to become a major challenge in the coming years. To address these issues, it is important to establish a resource-circulating society that promotes the efficient use of resources, minimizes waste, and enables the continuous recycling of materials, and to develop new functional materials. By integrating chemistry, materials science, and resource circulation engineering, it is possible to enhance regional industrial resilience, promote sustainable development, and create new high-value-added products.
This task force aims to build a resource-circulating society that simultaneously achieves high value addition through functionalization and a reduction in environmental impact. We are engaged in research on the synthesis and evaluation of next-generation high-performance luminescent and catalytic materials. In particular, our research focuses on exploring new applications for light rare-earth elements and developing catalytic materials utilizing waste glass.

Group members

Abstract

We are developing multi-core or multi-branch type of rare-earth-based high-temperature superconducting REBa2Cu3O7 (REBCO or RE123, RE: rare earth element)-coated conductors, having high critical current and low AC-loss, toward development of a high-current AC-cable and a high-performance AC-equipment. The commercially available RE123 coated-conductors have a single-core structure with non-negligible AC-loss. In order to reduce the loss, REBCO split wire (multi-core or multi-branch structure) with internal splits (artificial cracks) was proposed as shown in following figure. The multi-branched structure is fabricated with many intermittent cracks, and that is better for keeping the original critical current of the coated conductors. The purpose of this study is to experimentally evaluate the possibility of significantly improving AC-losses (e.g., 1/10 losses), while maintaining the critical current above 80%.