Resumen: We introduce a single-step lithography process based on Ga+-focused ion beam (FIB) irradiation to trigger a topotactic transformation on SrFeO3-d thin films, from the perovskite to the brownmillerite (BM) crystal structure. The crystallographic transformation is triggered by preferential oxygen sputtering by Ga+-FIB irradiation, which favors the formation of the SrFeO2.5 BM phase. The transformation has been verified through micro-Raman spectroscopy on thin films subjected to Ga+-FIB irradiation under 5 kV and 30 kV. Inducing crystallographic transformations by FIB in a single-step process (without the need of resists), at a very high speed (low Ga+ doses are required, in the range of 1015 ions/cm2), with very high spatial resolution (limited by the ion beam spot, of a few square nanometers) and with potential for upscaling using broad Ga+ beams, this approach represents a significant forward step over previous methods using multistep lithographic or electrochemical procedures. All these virtues make this process appealing to develop applications based not only on SrFeO3-d thin films but also on other oxide films harnessing topotactic transformations. Idioma: Inglés DOI: 10.1063/1.5141154 Año: 2020 Publicado en: Applied Physics Letters 116, 16 (2020), 163103 [1-5 pp.] ISSN: 0003-6951 Factor impacto JCR: 3.791 (2020) Categ. JCR: PHYSICS, APPLIED rank: 47 / 160 = 0.294 (2020) - Q2 - T1 Factor impacto SCIMAGO: 1.181 - Physics and Astronomy (miscellaneous) (Q1)