Characterization of epitaxial LSMO thin films with high Curie temperature prepared on different substrates

• Epitaxial La0.67Sr0.33MnO3 (LSMO) films are grown on SrTiO3, LaAlO3, La0.26Sr0.76 Al0.61Ta0.37O3 and MgO substrates.
• LSMO films exhibit high Curie temperature TC and metal-insulator transition temperature TMI in temperature range 405–450 K.
• TC (TMI) is analyzed with respect to substrate-induced strain.
• Increased TC (TMI) values are ascribed to decreasing strength of electron-phonon coupling.
• Substrate-induced strain slightly reduces TC (TMI) values.

We investigated structural, electrical and magnetic properties of epitaxial La0.67Sr0.33MnO3 (LSMO) thin films (20–100 nm thick) deposited by pulsed laser ablation on different substrates. Single crystalline substrates: (001) SrTiO3, (001) LaAlO3, (001) La0.26Sr0.76Al0.61Ta0.37O3 and (001) MgO were used to vary the substrate-induced epitaxial strain. The LSMO films exhibit very good crystal quality and enhanced temperatures of metal-insulator transition (TMI) as well as temperature of ferromagnetic ordering (Curie temperature, TC) up to 451 K with TMI = TC coincidence of both temperatures. The enhanced TC (TMI) values were analyzed with respect to substrate-induced strain and LSMO film thickness. We ascribe the increased TC (TMI) values to decreasing strength of electron-phonon coupling coming from Jahn-Teller splitting. The substrate-induced strain in the LSMO films only decreased the TC (TMI) values depending on magnitude of biaxial strain.