Magneto-optical properties of cobalt and Co3O4 thin films: Influence of microstructural properties
Abstract
Two kinds of cobalt thin films, labeled smooth and nanostructured according to their surface properties, were deposited on a glass substrate by varying the deposition conditions during magnetron sputtering. Complementary characterization techniques were first used to investigate the internal microstructure of these two films, which give evidence that the smooth film structure is dense and close to bulk cobalt while the nanostructured film contains columnar-like structures of few nanometers’ width surrounded by an oxide layer. The smooth film shows a linear magnetic behavior, while a hysteresis loop has been observed for the nanostructured film, due to the presence of pinning-type domain wall motion. The nanostructured film is more porous to oxygen diffusion than the smooth one, which explains that its oxidation starts at lower annealing temperature than that of the smooth one. The spectral magneto-optical properties of the oxidized films were studied, revealing for the first time, three diamagnetic transitions at around 700, 1330, and 1450 nm, involving Co2+ and/or Co3+ ions. The blue shift observed for the nanostructured film highlights the impact of the initial morphology of the films on the cation's crystal coordination.
Article Details
Journal Info
Journal of Applied Physics
American Institute of Physics
Authors (12)
Gerges El Haber
CNRS, Institut d’Optique Graduate School, Laboratoire Hubert Curien UMR 5516, Université Jean Monnet Saint-Etienne 1 , Saint-Etienne F-42023,
François Goutaland
CNRS, Institut d’Optique Graduate School, Laboratoire Hubert Curien UMR 5516, Université Jean Monnet Saint-Etienne 1 , Saint-Etienne F-42023,
Dominique Luneau
Laboratoire des Multimatériaux et Interfaces (UMR CNRS 5615), Université Claude Bernard Lyon 1 2 , Villeurbanne F-696100,
Damien Jamon
CNRS, Institut d’Optique Graduate School, Laboratoire Hubert Curien UMR 5516, Université Jean Monnet Saint-Etienne 1 , Saint-Etienne F-42023,
Jean Pierre Chatelon
CNRS, Institut d’Optique Graduate School, Laboratoire Hubert Curien UMR 5516, Université Jean Monnet Saint-Etienne 1 , Saint-Etienne F-42023,
Jean Yves Michalon
CNRS, Institut d’Optique Graduate School, Laboratoire Hubert Curien UMR 5516, Université Jean Monnet Saint-Etienne 1 , Saint-Etienne F-42023,
Nadège Ollier
CNRS, Institut d’Optique Graduate School, Laboratoire Hubert Curien UMR 5516, Université Jean Monnet Saint-Etienne 1 , Saint-Etienne F-42023,
Christophe Donnet
CNRS, Institut d’Optique Graduate School, Laboratoire Hubert Curien UMR 5516, Université Jean Monnet Saint-Etienne 1 , Saint-Etienne F-42023,
Yannick Bleu
CNRS, Institut d’Optique Graduate School, Laboratoire Hubert Curien UMR 5516, Université Jean Monnet Saint-Etienne 1 , Saint-Etienne F-42023,
Yaya Lefkir
CNRS, Institut d’Optique Graduate School, Laboratoire Hubert Curien UMR 5516, Université Jean Monnet Saint-Etienne 1 , Saint-Etienne F-42023,
Stephanie Reynaud
François Royer
CNRS, Institut d’Optique Graduate School, Laboratoire Hubert Curien UMR 5516, Université Jean Monnet Saint-Etienne 1 , Saint-Etienne F-42023,