Segregation and Near‐Surface Diffusion for Undoped and Cr‐Doped CoO

Abstract

Work function measurements were used to monitor the re‐equilibration kinetics for the system CoO‐Cr 2 O 3 involving undoped CoO, Cr‐doped CoO, CoCr 2 O 4 spinel phase, and undoped Cr 2 O 3 . The activation energy of chemical diffusion for the near‐surface layer was determined for these materials. Combined work function, X‐ray, and ESCA studies indicate that Cr segregates in CoO‐Cr z O 3 solid solutions, which leads to the formation of a new “surface phase” of spinel‐like structure.