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RRJOMS | Volume 5 | Issue 7 | November, 2017
Periodic nanostructures obtained by spinodal decomposition at low temperature on Co
1.7
Fe
1.3
O
4
thin films
prepared by radio frequency sputtering
A. Barnabe, L Presmanes, M.A. Bui, T.M.C. Dinh., H. Le Trong
and
P. Tailhades,
CIRIMAT – Université de Toulouse III Paul Sabatier, Toulouse France
I
nside a miscibility gap of a phase diagram, a homogeneous solid solution is not stable and progressively broken down into two
different phases either by nucleation/growth or spinodal decomposition. Spinodal transformation which only operates in a limited
area of the gap, can induce periodic microstructures at a submicronic scale. When they contain at least a magnetic ordered phase,
such microstructures could then be a key step in the quest for materials with original properties such as giant magnetoresistance,
and/or magnonic crystal which are likely to find new technological applications. In the CoFe
2
O
4
–Co
3
O
4
phase diagram there is a
miscibility gap in which spinodal decomposition can lead to regular alternation of ordered magnetic phases made of spinel oxides.
This was mainly observed in powders. In the context of potential future applications, it is however necessary to be able to prepare thin
films and to induce in them spinodal decomposition at low temperatures. The purpose of this study is devoted to 1) the preparation
of Co
1.7
Fe
1.3
O
4
spinel iron cobaltite thin films on cheap substrate, 2) the structuration at the nanoscale by spinodal transformation at
moderate temperatures and 3) the characterization at the nanoscale on the spinodal transformation. Pure thin films of Co
1.7
Fe
1.3
O
4
spinel iron cobaltites were prepared by rf sputtering. The two-phase spinels obtained through the spinodal transformation were
evidenced after annealing in air at low temperature by XRD/TEM/Raman/Mossbauer/electrical measurements studies. Specific in-
plane sections elaborated by FIB were carried out and analyzed by high resolution TEM studies coupled with EELS/EDS/STEM
elemental analysis at the atomic scale. From the present work it can then be concluded that the preparation of Co
1.7
Fe
1.3
O
4
thin films
structured by spinodal transformation could be obtained at temperatures compatible with the use of cheap substrates.
Biography
A. Barnabé is a professor at the CIRIMAT laboratory (Mixed Oxide Valency research group), Paul Sabatier University, France. He received his PhD degree in chemistry of
materials from University de Caen-Basse Normandie (France) in 1999. He held a post-doctoral position in Northwestern University, Evanston (USA), in 2000. His current
research interests are mainly focused in functional metal oxide powders, ceramics and thin films prepared by PVD technique. He first worked on TEM characterization of
giant magnetoresistance manganites then moves to complex oxides with new optoelectronic properties. For the last decade, he has developed transparent conductive
oxides (n- and p-type) and gas-sensing layers for the CO
2
detection sputtered oxide thin films. He’s in charge on the SEM/TEM/EPMA/SIMS characterization center R.
CASTAING in Toulouse. To date, all these works have led to 63 publications, 2 patents, and more than 80 communications (hindex = 22, sum of the times cited > 1400).
barnabe@chimie.ups-tlse.frA. Barnabe et al., Res. Rev. J Mat. Sci. 2017, 5:7
DOI: 10.4172/2321-6212-C1-012