Crystal chemistry and physical properties of 3d transition metal nitrides derived by chemical reaction at sub-megabar pressure range

2017 Fiscal Year Final Research Report

• Project/Area Number: 15H05542
• Research Category: Grant-in-Aid for Young Scientists (A)
• Allocation Type: Single-year Grants
• Research Field: Physical properties of metals/Metal-base materials
• Research Institution: Nagoya University
• Principal Investigator: NIWA Ken 名古屋大学, 工学研究科, 准教授 (40509030)
• Project Period (FY): 2015-04-01 – 2018-03-31
• Keywords: 窒化物 / 結晶構造 / 電子 / 磁性

Outline of Final Research Achievements

Highly coordinated iron, cobalt, nickel and copper nitrides were successfully synthesized via direct chemical reaction between a transition metal and molecular nitrogen at the pressures above approximately 30 GPa. The high pressure in-situ X-ray diffraction and Raman scattering measurements revealed that the synthesized novel transition metal nitrides were found to crystallize into the NiAs-type, marcasite-type or CdI2-type structures, in which NiAs-type FeN and marcasite-type CoN2 could be quenched at ambient pressure while marcasite-type NiN2 and CdI2-type CuN2 were found to be unstable at ambient pressure. A first-principles electronic band calculation suggests that the NiAs-type FeN and marcasite-type CoN2 exhibit metallic characteristics. The present results indicate that the crystal structures are based on the hexagonal closed packing arrangement of nitrogen atoms and the transition metal atoms occupy the highly coordinated octahedral sites.

Free Research Field

超高圧結晶化学