Epitaxial growth and properties of La0.7Sr0.3MnO3 thin films with micrometer wide atomic terraces

TL;DR

This study reports the epitaxial growth of La0.7Sr0.3MnO3 thin films with ultra-wide atomic terraces on SrTiO3 substrates, analyzing their structural, magnetic, and electronic properties and how they improve with post-annealing.

Contribution

It demonstrates the growth of LSMO films with unprecedented atomic terrace width and investigates their magnetic and transport properties as a function of thickness and post-annealing.

Findings

Atomic terraces wider than 2 micrometers observed.

Magnetization of 255 emu/cm3 at room temperature for 20 MLs.

Post-annealing enhances electron transport and magnetic properties.

Abstract

La0.7Sr0.3MnO3 (LSMO) films with extraordinarily wide atomic terraces are epitaxially grown on SrTiO3 (100) substrates by pulsed laser deposition. Atomic force microscopy measurements on the LSMO films show that the atomic step is ~ 4 {\AA} and the atomic terrace width is more than 2 micrometers. For a 20 monolayers (MLs) LSMO film, the magnetization is determined to be 255 +- 15 emu/cm3 at room temperature, corresponding to 1.70 + - 0.11 Bohr magneton per Mn atom. As the thickness of LSMO increases from 8 MLs to 20 MLs, the critical thickness for the temperature dependent insulator-to-metal behavior transition is shown to be 9 MLs. Furthermore, post-annealing in oxygen environment improves the electron transport and magnetic properties of the LSMO films.