Control of the Electrical Properties in Spinel Oxides by Manipulating the Cation Disorder. (29th October 2013)

• Record Type: Journal Article
• Authors: Ndione, Paul F.; Shi, Yezhou; Stevanovic, Vladan; Lany, Stephan; Zakutayev, Andriy; Parilla, Philip A.; Perkins, John D.; Berry, Joseph J.; Ginley, David S.; Toney, Michael F.
• Is Part Of: Advanced functional materials. Volume 24:Number 5(2014)
• Page Start: 610
• Page End: 618
• Publication Date: 2013-10-29
• Subjects: cation disorder -- spinels -- conductivity -- annealing -- nickel cobalt oxides -- zinc cobalt oxides; Materials -- Periodicals; Chemical vapor deposition -- Periodicals; 620.11
• DOI: 10.1002/adfm.201302535
• Languages: English
• ISSNs: 1616-301X

Abstract

Abstract : In this work, the impact of cation disorder on the electrical properties of biaxially textured Co2 ZnO4 and Co2 NiO4 thin films grown by pulsed laser deposition are investigated using a combination of experiment and theory. Resonant elastic X‐ray diffraction along with conductivity measurements both before and after post‐deposition annealing show that Co2 ZnO4 and Co2 NiO4 exhibit opposite changes of the conductivity with cation disorder, which can be traced back to their different ground‐state atomic structures, being normal and inverse spinel, respectively. Electronic structure calculations identify a self‐doping mechanism as the origin of conductivity. A novel thermodynamic model describes the non‐equilibrium cation disorder in terms of an effective temperature. This work offers a way of controlling the conductivity in spinels in a quantitative manner by controlling the cation disorder and a new design principle whereby non‐equilibrium growth can be used to create beneficial disorder. Abstract : A combination of experiment and theory quantifies the dependence of the conductivity in Co2 ZnO4 and Co2 NiO4 on the cation disorder. A self‐doping mechanism is identified as the origin of conductivity and a thermodynamic model is used to describe the non‐equilibrium cation disorder in terms of an effective temperature. The conductivity in spinels can be controlled by manipulating the cation disorder.