DIRECT MEASUREMENT OF STRAIN EFFECTS ON MAGNETIC AND ELECTRICAL-PROPERTIES OF EPITAXIAL SRRUO3 THIN-FILMS

By lifting an epitaxial thin film off its growth substrate, rye direct ly and quantitatively demonstrate how elastic strain can alter the mag netic and electrical properties of single-domain epitaxial SrRuO3 thin films (1000 Angstrom thick) on vicinal (001) SrTiO3 substrates. Free- standing films were then obtained by selective chemical etching of the SrTiO3. X-ray diffraction analysis shows that the free-standing films are strain free, whereas the original as-grown films an SrTiO3 substr ates are strained due to the lattice mismatch at the growth interface. Relaxation of the lattice strain resulted in a 10 K increase in the C urie temperature to 160 K, and a 20% increase in the saturation magnet ic moment to 1.45 mu(B)/Ru atom. Both values for the free-standing fil ms are the same as that of the bulk, single crystals. Our results prov ide direct evidence of the crucial role of the strain effect in determ ining the properties of the technologically important perovskite epita xial thin films. (C) 1998 American Institute of Physics.