For most epitaxially-grown manganite thin films, they either stretch or compress their bond length in reaction to the misfit strain. However, a strikingly different way to accommodate the misfit strain has been observed in epitaxially grown La1-xSrxMnO3 thin films on SrTiO3 (100). Periodic, one-dimensional micro-twinning patterns form spontaneously during cooling from the growth temperature in order to adapt simultaneously the misfit from both bond length and bond angle between the cubic STO substrate and the rhombohedral LSMO film. The twinning modulation wavelength was observed to increase with increasing thickness and condensed into conventional twin domains for thicken films. This epitaxial strain induced micro-twinning pattern only exists in the thin film regime and induces interesting new phenomena which are not seen in their bulk counterparts.
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