skip to main content

DOE PAGESDOE PAGES

This content will become publicly available on November 9, 2016

Title: Synthesis, Hardness, and Electronic Properties of Stoichiometric VN and CrN

Here, we report synthesis of single-crystal VN and CrN through high-pressure ionexchange reaction routes. The final products are stoichiometric and have crystallite sizes in the range of 50-120 mu m. We also prepared VN and TiN crystals using high-pressure sintering of nitride powders. On the basis of single-crystal indentation testing, the determined asymptotic Vickers hardness for TiN, VN, and CrN is 18 (1), 10 (1), and 16 (1) GPa, respectively. Moreover, the relatively low hardness in VN indicates that the metallic bonding prevails due to the overfilled metallic a bonds, although the cation-anion covalent hybridization in this compound is much stronger than that in TiN and CrN. All three nitrides are intrinsically excellent metals at ambient pressure. In particular, VN exhibits superconducting transition at T-c approximate to 7.8 K, which is slightly lower than the reported values for nitrogen-deficient or crystallinedisordered samples due to unsuppressed "spin fluctuation" in the well-crystallized stoichiometric VN. The magnetostructural transition in CrN correlates with a metal metal transition at T-N = 240(5) K and is accompanied by a similar to 40% drop in electrical resistivity. Additionally, more detailed electronic properties are presented with new insights into these nitrides.
Authors:
 [1] ;  [2] ;  [3] ;  [4] ;  [5] ;  [6] ;  [4]
  1. Univ. of Nevada, Las Vegas, NV (United States); Sichuan Univ., Chengdu (China)
  2. Chinese Academy of Sciences (CAS), Beijing (China)
  3. Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
  4. Univ. of Nevada, Las Vegas, NV (United States)
  5. Arizona State Univ., Tempe, AZ (United States)
  6. Sichuan Univ., Chengdu (China)
Publication Date:
OSTI Identifier:
1261496
Grant/Contract Number:
AC05-00OR22725
Type:
Accepted Manuscript
Journal Name:
Crystal Growth and Design
Additional Journal Information:
Journal Volume: 16; Journal Issue: 1; Journal ID: ISSN 1528-7483
Publisher:
American Chemical Society
Research Org:
Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States)
Sponsoring Org:
USDOE National Nuclear Security Administration (NNSA)
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY transition-metal nitrides; vickers hardness; ion-exchange reaction; high-pressure synthesis