Vacancy formation and recovery phenomena during hydrogenation and dehydrogenation in La(Ni,Cu)5+x

• Project/Area Number: 25820361
• Research Category: Grant-in-Aid for Young Scientists (B)
• Allocation Type: Multi-year Fund
• Research Field: Structural/Functional materials
• Research Institution: National Institute of Advanced Industrial Science and Technology
• Principal Investigator: SAKAKI Kouji 国立研究開発法人産業技術総合研究所, 創エネルギー研究部門, 主任研究員 (20392615)
• Project Period (FY): 2013-04-01 – 2016-03-31
• Project Status: Completed (Fiscal Year 2015)
• Budget Amount: ¥4,290,000 (Direct Cost: ¥3,300,000、Indirect Cost: ¥990,000); Fiscal Year 2015: ¥780,000 (Direct Cost: ¥600,000、Indirect Cost: ¥180,000); Fiscal Year 2014: ¥780,000 (Direct Cost: ¥600,000、Indirect Cost: ¥180,000); Fiscal Year 2013: ¥2,730,000 (Direct Cost: ¥2,100,000、Indirect Cost: ¥630,000)
• Keywords: 水素吸蔵 / 相変態 / 空孔 / 陽電子消滅

Outline of Final Research Achievements

The vacancy formation and recovery phenomena during hydrogenation and dehydrogenation in La(Ni,Cu)5+x were investigated. The positron lifetime increased upon hydrogenation and dehydrogenation in all samples which we synthesized. However, its increment was suppressed with increasing of the deviation from the stoichiometry. X-ray diffraction results showed that the lattice misfit decreased and concentration of dumbbell pairs increased with increasing of the deviation from the stoichiometry. Therefore, it suggests that the vacancy formation was suppressed by smaller lattice misfit and/or the vacancy recovery was enhanced by increase of concentration of dumbbell pairs.