Impacts of compressive strain on phase diagram of epitaxial Pr0.5Sr0.5MnO3 films grown on LaAlO3 (0 0 1)

Series Pr_0.5Sr_0.5MnO₃ (PSMO) films of thickness ranging from 20 to 400 nm were epitaxially grown on (0 0 1)-oriented LaAlO₃ using pulsed laser deposition method. The biaxial compressive strain effect on phase transition of the films was systematically investigated by both electrical and magnetic measurements. The 60 nm film shows a ferromagnetic metal to antiferromagnetic insulator (FMM-AFI) transition at a temperature of ∼190 K. Such a FMM-AFI transition is depressed as the films become thicker, and finally disappears in the strain-relaxed situation. On the other hand, the Curie temperature is remarkably enhanced (∼50 °C) when the film thickness increases from 60 to 400 nm. These results may yield the possibility to modulate the phase transitions by varying the structural strain.