On the first evidence of exchange-bias feature in magnetically contrasted consolidates made from CoFe2O4-CoO core-shell nanoparticles

Nancy Flores-Martinez (1) , Giulia Franceschin (1) , Thomas Gaudisson (1) , Sonia Haj-Khlifa (1) , Sarra Gam Derouich (1) , Nader Yaacoub (2) , Jean-Marc Greneche (2) , Nicolas F Menguy (3) , Raul Valenzuela (4) , Souad Ammar (1)

1 ITODYS (UMR_7086) - Interfaces, Traitements, Organisation et Dynamique des Systèmes
2 IMMM - Institut des Molécules et Matériaux du Mans
3 IMPMC - Institut de minéralogie, de physique des matériaux et de cosmochimie
4 Instituto de Investigaciones en Materiales (Mexico, Mexico)

Hetero-nanostructures based on magnetic contrast oxides have been prepared as highly dense nanoconsolidates. Cobalt ferrite-cobalt oxide core-shell type nanoparticles (NPs) were synthesized by seed mediated growth in polyol and subsequently consolidated by Spark Plasma Sintering (SPS) at 500 °C for a few minutes while applying a uniaxial pressure of 100 MPa. It is interesting to note that the exchange bias feature observed in the core-shell NPs is reproduced in their ceramic counterparts, or even attenuated. A systematic structural characterization was then carried out to elucidate the decrease in the exchange magnetic field, involving mainly advanced X-ray diffraction, zero-field and in-field 57Fe Mössbauer spectrometry, magnetic measurements and electron microscopy.

Domaines: Matière Condensée [cond-mat]; Physique [physics]

Nancy Flores-Martinez, Giulia Franceschin, Thomas Gaudisson, Sonia Haj-Khlifa, Sarra Gam Derouich, et al.. On the first evidence of exchange-bias feature in magnetically contrasted consolidates made from CoFe2O4-CoO core-shell nanoparticles. Scientific Reports, 2019, 9, pp.19468. ⟨10.1038/s41598-019-55649-y⟩. ⟨hal-02441279⟩