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Room‐Temperature AFM Electric‐Field‐Induced Topotactic Transformation between Perovskite and Brownmillerite SrFeO x with Sub‐Micrometer Spatial Resolution
Author(s) -
FerreiroVila Elías,
BlancoCanosa Santiago,
Lucas del Pozo Irene,
Vasili Hari Babu,
Magén César,
Ibarra Alfonso,
RubioZuazo Juan,
Castro Germán R.,
Morellón Luis,
Rivadulla Francisco
Publication year - 2019
Publication title -
advanced functional materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 6.069
H-Index - 322
eISSN - 1616-3028
pISSN - 1616-301X
DOI - 10.1002/adfm.201901984
Subject(s) - brownmillerite , materials science , perovskite (structure) , electric field , ionic bonding , micrometer , electrical resistivity and conductivity , fabrication , oxide , oxidizing agent , nanotechnology , ion , chemical physics , optoelectronics , crystallography , optics , chemistry , metallurgy , physics , electrical engineering , organic chemistry , quantum mechanics , engineering , medicine , alternative medicine , pathology
Reversible structural transformations between perovskite (PV) ABO 3− δ and brownmillerite (BM) ABO 2.5 (A = Ca 2+ , Sr 2+ ; B = Fe 4+/3 , Co 4+/3+ ) oxides can be induced by topotactic oxygen exchange at moderate temperatures under reducing/oxidizing conditions. The combination of a large oxide‐ion conductivity and a small free energy difference between the 4+/3+ oxidation states of many 3d transition metal ions enables these topotactic transformations. Herein, it is demonstrated that the electric field produced by a voltage‐biased atomic force microscopy tip can induce such transformation between PV SrFeO 3− δ and BM SrFeO 2.5 at room temperature and with sub‐micrometer spatial resolution. Interestingly, the structural transformation is kept after the electric field is removed, allowing a nonvolatile control of the local chemical, electrical, optical, and magnetic properties. Thus, the results presented in this paper open the door for the fabrication of stable ionic‐based devices through the electric field patterning of different crystallographic phases.