Pulsed laser ablation has been used to deposit thin films of SrFeO25+x (x = 0 to ≈0.5). Previous work has shown that the orientation of the films, determined by powder x-ray diffraction depended strongly upon the deposition temperature. Films grown below 770 K showed little or no orientation. A growth temperature of 900 K resulted in films oriented (200). Growth temperatures of > 1000 K produced films oriented predominantly (110). At 673 K in an oxygen atmosphere, oriented films readily converted from the oxygen deficient brownmillerite form (x=0) to the oxygen rich cubic (or distorted cubic) perovskite form (x≈0.3). Films which exhibited no initial orientation did not react with oxygen under these conditions. Cycling non-oriented films between 230 and 800 ppm of oxygen in 101.3 kPa of nitrogen at 673 K resulted in weak (110) orientation. Once oriented, the films reacted readily with oxygen and exhibited measurable resistance changes. The conversion from oxygen deficient to oxygen rich form was monitored by x-ray diffraction and the DC resistance of the films.
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