KrF pulsed laser deposition of chromium oxide thin films from Cr8O21 targets

TL;DR

This study explores the use of KrF pulsed laser deposition to grow chromium oxide thin films from Cr8O21 targets, aiming to synthesize metastable CrO2 at low temperatures for spintronic applications.

Contribution

It demonstrates the feasibility of using PLD with Cr8O21 targets to produce amorphous chromium oxide films containing nanocrystals of Cr2O3 and possibly CrO2, advancing low-temperature synthesis methods.

Findings

Films are amorphous with dispersed Cr2O3 nanocrystals.

Possible co-deposition of Cr2O3 and CrO2 detected.

Processing parameters influence stoichiometry and structure.

Abstract

Chromium oxides, CrxOy, are of great interest due to the wide variety of their technological applications. Among them, CrO2 has been extensively investigated in recent years because it is an attractive compound to be used in spintronic heterostructures. However, its synthesis at low temperatures has been a difficult task due to the metastable nature of this oxide. This is indeed essential to ensure interface quality and the ability to coat thermal-sensitive materials such as those envisaged in spintronic devices. Pulsed Laser Deposition (PLD) is a technique that has the potential to meet the requirements stated above. In this work, we describe our efforts to grow chromium oxide thin films by PLD from Cr8O21 targets, using a KrF excimer laser. The as-deposited films were investigated by X-ray diffraction and Rutherford backscattering spectrometry. Structural and chemical composition studies showed that the films consist of a mixture of amorphous chromium oxides exhibiting different stoichiometries depending on the processing parameters, where nanocrystals of mainly Cr2O3 are dispersed. The analyses do not exclude the possibility of co-deposition of Cr2O3 and a low fraction of CrO2. PACS: 81.15.Fg, 75.50.Dd