Nanoscale structural characterization of manganite thin films integrated to silicon correlated with their magnetic and electric properties

TL;DR

This study provides a detailed nanoscale structural analysis of La0.66Sr0.33MnO3 thin films on silicon, linking their epitaxial growth, interface quality, and strain effects to their magnetic and electrical properties.

Contribution

It offers new insights into the nanoscale structure, epitaxial relationships, and strain effects in manganite thin films integrated with silicon, using advanced characterization techniques.

Findings

LSMO films are ferromagnetic and metallic at low temperatures regardless of thickness.

Strain and defects are significant only in films thinner than 15 nm.

Sharp interfaces and epitaxial growth were confirmed with no ion interdiffusion.

Abstract

A detailed nanoscale structural characterization was performed on high-quality La0.66Sr0.33MnO3 (LSMO) thin films of different thicknesses and deposited by pulsed laser deposition onto buffered Si (100) substrates. A multilayered structure built of Y0.13Zr0.87O2 (YSZ) and CeO2 layers was used as buffer in order to optimize the manganite films growth. The stacking of the different layers, their morpholohy, composition and strains were analysed using different experimental techniques. In-situ characterization of the films, performed with reflection high-energy electron diffraction, revealed their epitaxial growth and smooth surfaces. High-resolution transmission electron microscopy (HR-TEM) images showed sharp interfaces between the constituents lattices and combined with energy-dispersive X-ray analysis allowed us to determine that there was no ion interdifussion across them. The Fourier-Fast-Transform of the HR-TEM images was used to resolve the epitaxy relationship between the layers, resulting in [100] LSMO (001) // [110] CeO2 (001) // [110] YSZ (001) // [110] Si (001). The LSMO thin films were found to be ferromagnetic and metallic at low temperature regardless their thickness. The effect of strains and defects was only detected in films thinner than 15 nm and put in evidence by X-ray diffraction patterns and correlated with magnetic and electrical parameters.