| Project/Area Number |
05452095
|
|---|
| Research Category |
Grant-in-Aid for General Scientific Research (B)
|
| Allocation Type | Single-year Grants |
|---|
| Research Field |
Applied materials science/Crystal engineering
|
|---|
| Research Institution | Yokohama National University |
|---|
Principal Investigator |
YAMAGUCHI Masuhiro Yokohama Nat.Univ., Dept.Eng.Professor, 工学部, 教授 (10018046)
|
|---|
| Co-Investigator(Kenkyū-buntansha) |
GOTO Tsuneaki Univ.Tokyo, ISSP,Professor, 物性研究所, 教授 (30005962)
YAMAMOTO Isao Yokohama Nat.Univ., Dept.Eng.Assistant, 工学部, 助手 (40242383)
KAKUNO Keiichi Yokohama Nat.Univ., Dept.Eng.Professor, 工学部, 教授 (40017918)
|
|---|
| Project Period (FY) |
1993 – 1994
|
| Project Status |
Completed (Fiscal Year 1994)
|
| Budget Amount *help |
¥5,700,000 (Direct Cost: ¥5,700,000)
Fiscal Year 1994: ¥1,800,000 (Direct Cost: ¥1,800,000)
Fiscal Year 1993: ¥3,900,000 (Direct Cost: ¥3,900,000)
|
|---|
| Keywords | Metal hydride / Single crystal / Electrical resistivity / Magnetization / 磁化 |
|---|
| Research Abstract |
The present study was concerned with (1) the formation of well-defined and large single crystals of metal hydrides and (2) the investigation of electric and magnetic properties for these metal hydrides. We investigated the ternary metal hydrids based on rare-eath intermetallics, such as LaNi_5, LaCo_5, GdFe_3, Gd_6Fe_<23>, Mg_2Ni, NdCo_5, YCo_3, Y_6Fe_<23>.
The single crystals of the starting intermetallics were prepared by means of triarcmelting. Laue x-ray diffraction patterns showed that they were single crystals and the maximum size of them was 8mm d*20mm l.
We developed an in situ method to measure the electrical resistivity unstable hydrides (with high equilibrium hydrogen pressures). It was observed that Mg_2Ni transits from a metal to a semiconductor as a result of hydrogenation and the energy gap of Mg_2NiH_<3.1> is 0.056eV.
As hydrogen is absorbed in GdFe_3, the lattice constants is increased and the compensation temperature is decreased from 280K to 161K.Under the influence of high magnetic fields, the magnetic structure of GdFe_3H_X transits from a simple ferrimagnetic one to a non-colinear one. Its critical fields decreased from 24.7T to 13.0T.The strength of the exchange interaction depends on the hydrogen composition x judging from the variation in the exchange coupling constant.
|
