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(Magic Dopant) Amphoteric Behavior of a Redox-Active Transition Metal Ion in a Perovskite Lattice: New Insights on the Lattice Site Occupation of Manganese in SrTiO3

Published

Author(s)

Russell A. Maier, Matthew P. Donohue

Abstract

It is definitively shown for the first time that a transition metal, redox-active ion can exhibit amphoteric substitution in the SrTiO3 perovskite lattice. The manganese dopant is preferably accommodated as Mn2+ on the strontium site and as Mn4+ on the titanium site. Previous studies have suggested either type of substitution is possible for compositions with ideal Sr/Ti stoichiometry. However, it is shown, using Electron Paramagnetic Resonance (EPR), that manganese ions prefer amphoteric substitution for stoichiometric Sr/Ti cation ratios. The tuned Sr/Ti ratio can be used to manipulate the nature of the manganese substitution, and it is shown that large Sr/Ti ratios result in purely B-site doping. For B-site substituted manganese ions, a new EPR signal for Mn2+ on the B-site is discovered in reduced compositions. Amphoteric doping is usually only considered for large, rare-earth ions that have limited numbers of preferred valence states compared to transition metal ions. With improved control over the site of substitution and valence state, amphoteric doping of a transition metal redox- active ion offers the possibility to build new electronic functionality into the perovskite lattice.
Citation
Advanced Functional Materials

Keywords

Perovskite, Point Defect, Amphoteric, Oxygen Vacancy, EPR

Citation

Maier, R. and Donohue, M. (2016), (Magic Dopant) Amphoteric Behavior of a Redox-Active Transition Metal Ion in a Perovskite Lattice: New Insights on the Lattice Site Occupation of Manganese in SrTiO3, Advanced Functional Materials, [online], https://doi.org/10.1002/adfm.201602156 (Accessed October 23, 2021)
Created October 5, 2016, Updated November 10, 2018