Thin films of Co1.7Fe1.3O4 prepared by radio frequency sputtering - the first step towards their spinodal decomposition

Thi Mai Anh Bui (1) , Hoa Le Trong (1) , Lionel Presmanes (1) , Antoine Barnabé (1) , Corine Bonningue (1) , Philippe Tailhades (1, 2)

1 CIRIMAT - Centre interuniversitaire de recherche et d'ingenierie des matériaux
2 HCMUS - Ho Chi Minh City University of Science

Pure thin films of Co1.7Fe1.3O4 spinel iron cobaltites were prepared for the first time by radio frequency sputtering. Such films are made of small crystallites of about 20 to 30 nm in diameter. Because Co1.7Fe1.3O4 films have a composition located in the miscibility gap of Fe3O4-Co3O4, they can be submitted to spinodal transformation below about 900 °C. This transformation was also confirmed at 600 °C by X-ray diffraction and transmission electron microscopy studies. It was demonstrated however that this spinodal transformation occurs after only a few hours at low temperature. Indeed, after annealing in air at 300 to 450 °C for a few hours, the spinodal transformation leading to two-phase spinels, one rich in iron and the other rich in cobalt, was clearly revealed by Raman spectroscopy and electrical measurements.

Mots clés: Spinodal decomposition; Iron cobaltites; Ferrimagnetic films; Spinel oxides; Phase transformation; Magnonic crystals; Sputtering; Spinodal decomposition

Domaines: Matériaux

Thi Mai Anh Bui, Hoa Le Trong, Lionel Presmanes, Antoine Barnabé, Corine Bonningue, et al.. Thin films of Co1.7Fe1.3O4 prepared by radio frequency sputtering - the first step towards their spinodal decomposition. CrystEngComm, 2014, n° 16, pp. 3359-3365. ⟨10.1039/c3ce42588f⟩. ⟨hal-01067955⟩