Thermodynamic CoO–Co3O4 crossover using Raman spectroscopy in magnetic octahedron‐shaped nanocrystals

This work describes the effect of the laser power and the exposure time on a sample of octahedron‐shaped nanocrystals of cobalt(II) oxide using Raman spectroscopy. Above a certain value of the laser power and exposure time, CoO rock salt sample evolves clearly to the oxidized Co 3 O 4 normal spinel material because of the energy transfer and consequent local heating induced by the applied laser. The analysis of this thermodynamic CoO–Co 3 O 4 crossover in octahedron‐shaped nanocrystals by means of the Raman spectroscopy has been performed. Copyright © 2017 John Wiley & Sons, Ltd.