Analysis of Cation Valences and Oxygen Vacancies in Magnetoresistive Oxides by Electron Energy-Loss Spectroscopy

Abstract

Magnetic oxides of (La,A)MnO₃ and (La,A)CoO₃ have two typical structural characteristics: cations with mixed valences and oxygen vacancies, which are required to balance the charge introduced by cation doping. The consequences introduced by each can be different, resulting in different properties. It is important to quantitatively determine the percentage of charges balanced by each, but this analysis is rather difficult particularly for thin films. This paper has demonstrated that electron energy-loss spectroscopy (EELS) can be an effective technique for analyzing Mn and Co magnetic oxides with the use of intensity ratio of white lines, leading to a new technique for quantifying oxygen vacancies in functional and smart materials.