Probing the bulk ionic conductivity by thin film hetero-epitaxial engineering

Area of Science:

• Materials Science
• Solid State Chemistry
• Electrochemistry

Background:

• Highly textured thin films are crucial for studying bulk conductivity in oxygen ion conducting oxides.
• Epitaxial heterostructures help investigate strain effects on oxygen ion migration.
• Substrate requirements include good lattice matching and high-temperature electrical insulation.

Purpose of the Study:

• To fabricate an epitaxial heterostructure suitable for reliable electrical characterization of ionic conducting thin films.
• To develop a template platform for growing ordered thin films of samarium-doped ceria and yttria-stabilized zirconia.
• To measure the bulk conductivity and activation energies of these thin films.

Main Methods:

• Fabrication of a double buffer layer (BaZrO3 and SrTiO3) on MgO substrates.
• Epitaxial growth of (001) oriented thin films of 15% Sm-doped CeO2 and 8 mol% Y2O3 stabilized ZrO2.
• Measurement of bulk conductivities and activation energies.

Main Results:

• Successful fabrication of an epitaxial heterostructure with a double buffer layer on MgO.
• Growth of highly ordered, epitaxially oriented thin films of Sm-doped CeO2 and YSZ.
• Accurate measurement of bulk conductivities and activation energies, confirming the approach's validity.

Conclusions:

• The developed insulating template platform fulfills requirements for ordered film growth and electrical insulation.
• This platform enables reliable measurement of bulk conductivity in advanced electrolyte materials.
• The approach shows potential for characterizing other novel ionic conductivity materials.