Modelling of structural domains and elastic strain calculation in rhombohedral La_1−xSr_xMnO₃ films on (110) SrTiO₃

Abstract

As reported in the literature, structural domains in (110) oriented rhombohedral La_{1− x} Sr _x MnO₃ (LSMO) films on (110) SrTiO₃ show a pattern with alternating domain widths and inclined domain walls. An appropriate one-dimensional periodic domain model was developed and the non-uniform strain field in a coherently grown film was calculated by applying the coherency-defect approach. The strain is sharply peaked at the junction of the domain walls and the film/substrate interface. The dependence of the equilibrium domain-width ratio and domain-pattern period on film thickness was determined by minimizing the sum of elastic and domain-wall energies. The proposed domain structure can be formed only in a certain range of the film's crystal-structure data compared to the substrate. Corresponding composition-dependent structure data of LSMO are compiled.

Acknowledgments

This work was supported by the Deutsche Forschungsgemeinschaft (Forschergruppe 520). One of the authors (AER) was supported in part by RFBR (project 05-08-65503a). The authors thank Prof. J.S. Speck for encouraging motivation for this study and for carefully reading the manuscript.