Commercial La Al O 3 substrates were thermally cycled simulating a procedure similar to
those followed during Ti O 2 and Sn O 2 dilute magnetic semiconductors' film pulsed laser
deposition. Ferromagneticlike behavior was found in some substrates, in which metallic iron
impurities were detected by x-ray photoelectron spectroscopy and total reflection x-ray
fluorescence measurements. A thorough experimental investigation, using high resolution
techniques, showed that these impurities were introduced by the procedure used to fix the …