Strain, spin disorder, and thickness dependence of magneto-transport in Sm_(0.55)Sr_(0.45)MnO_3 films

摘要

The correlation between the strain, spin disorder, and the thickness dependence of the magneto-transport has been investigated in as-grown and post-annealed 25-300-nm thick films of Sm_(0.55)Sr_(0.45)MnO_3 (SSMO) deposited on SrTiO_3 (STO) and LaA1O_3 (LAO) substrates. In the post-annealed SSMO/LAO films, the epitaxial strain increases with a decreasing thickness; however, it is independent of the thickness of the post-annealed SSMO/STO films. In both cases, the reduction of the metal-insulator transition temperature with a decreasing thickness was observed. This behavior is attributed to an increasing compressive strain in the SSMO/ LAO films and to spin disorder effects in the SSMO/STO ones.