2003 Fiscal Year Final Research Report Summary
Synthesis and Characterization of Multi-Component Metal Nitrides
| Project/Area Number |
13450263
|
|---|
| Research Category |
Grant-in-Aid for Scientific Research (B)
|
| Allocation Type | Single-year Grants |
|---|
| Section | 一般 |
|---|
| Research Field |
Inorganic materials/Physical properties
|
|---|
| Research Institution | Tohoku University |
|---|
Principal Investigator |
SHIMADA Masahiko Tohoku University, Institute of Multidisciplinary Research for Advanced Materials (IMRAM), Professor, 多元物質科学研究所, 教授 (80029701)
|
|---|
| Co-Investigator(Kenkyū-buntansha) |
KUBOTA Shunichi Tohoku University, IMRAM, Research Associate, 多元物質科学研究所, 助手 (10271975)
YAMANE Hisanori Tohoku University, Center for Interdisciplinary Research, Professor, 学際科学国際高等研究センター, 教授 (20191364)
|
|---|
| Project Period (FY) |
2001 – 2003
|
| Keywords | multi-component nitride / functional nitride / flux method / reactive sintering method / crystal structure / electrical property / magnetic property |
|---|
| Research Abstract |
Three phases with antifluorite-type related structures were prepared in the Li_3N-Mg_3N_2 system. The Rietveld analyses for the X-ray powder diffraction patterns was carried out with nitrogen vacancy models for (Li_xMg_<1-x>)_3N_<2-x>(O<x<0.20) and (Li_xMg_<1-x>)_2N_<(2-x)2/3>(0.5<x<0.6). Li and Mg atoms in LiMgN are arranged orderly in the orthorhombic unit cell. For (Li_<1-x>Ni_x)_3N solid solution, the a-axis length increased and the c-axis length decreased with increasing Ni content x. The semiconducting behavior was observed at x=0-0.20 and the sample prepared at x=0.25 showed metallic conductivity that indicated delocalization of electrons. In the Li-Fe-N system, a new nitride was synthesized. The chemical formula suggested by Rietveld analysis was Li_7FeNi_<3.75>. This compound crystallizes in a cubic cell, space group (I-43m), a=9.782Å, and has an antifluorite-type related superstructure. Li_7FeN_<3.75> showed antiferromagnetism (T_N=40K).
Six new compounds BasCu_3In_4N_5,Ba<14>Cu_2In_4N_7,Sr_8Cu_3In_4N_5,Ba<0.73>Sr<0.28>CuN, Ba_6In_<4.72>N_3 and Ba_<19>In_9N_9 were found. In each compound, N atoms are surrounded by Ba or Sr and/or Cu atoms, and situated in the N atom centered octahedron of the metal atoms. These octahedra share apexes, edges, and faces, forming tunnel structures in Ba_8Cu_3In_4N_5 and Sr_8Cu_3In_4N_5,a three-dimensional network in Ba_6In_<4.72>N_3,and layered structure in Ba_<14>Cu_2In_4N_7,Ba_<0.73>Sr_<0.28>CuN and Ba_<19>In_9N_9. The Ba_8Cu_3In_4N_5 and Sr_8Cu_3In_4N_5 single crystal exhibited metallic conductivity.
|
