Morphology and stability in a half-metallic ferromagnetic CrO2 compound of nanoparticles synthesized via a polymer precursor

摘要

Nanoparticles of stable CrO2 of a half-metallic ferromagnet are synthesized with a novel chemical method involving a Cr4+-polymer composite precursor. A single phase CrO2 of D-4h(14):P4(2)/mnm tetragonal crystal structure (lattice parameters a = 0.4250 and c = 0.3190 nm) lies after firing the precursor at 350 degreesC for 1 h in air. Microstructure reveals single domain CrO2 particles of thin platelets (aspect ratio similar to1) of average 50 nm diameter and 35 nm thickness. In air, unless heating at temperatures above 500 degreesC, no due CrO2 --> Cr2O3 phase transformation encounters. The results are presented in terms of X-ray diffraction and thermal or thermogravimetric analysis of precursor and derived CrO2 powder. (C) 2004 Elsevier B.V. All rights reserved.