Homogeneous strain-relaxation effects in La 0.67 Ca 0.333 MnO 3 films grown on NdGaO 3

S. SEIRO; E. KOLLER; YANINA FASANO; \O. FISCHER

APPLIED PHYSICS LETTERS

Año: 2007 vol. 91 p. 91913 - 91916

0003-6951

X-ray diffraction and transport measurements on a series of La0.67Ca0.33MnO3 films grown on (110)-cut NdGaO3 substrates are presented. Contrary to widespread belief assuming strain-free growth, this work shows the presence of strain in a 42  nm film. On increasing thickness structural relaxation occurs, reaching a bulklike state for 500  nm. No evidence of coexistence of strained and relaxed regions is found. The evolution of lattice parameters toward bulk values is accompanied by an increase of the metal-to-insulator transition temperature and a decrease of the polaron activation energy. Therefore, strain effects cannot always be neglected in La0.67Ca0.33MnO3 films grown on small-mismatch NdGaO3.