Structural and magnetic properties of the (Ca1-xNax)(Fe2-xTix)O4 solid solution (0 x 1)

Siwar Zouari (1) , Laurent Ranno (2) , Abdelwaheb Cheikh-Rouhou (1) , Olivier Isnard (3) , Pierre Wolfers (3) , Pierre Bordet (3) , Pierre Strobel (3)

1 Laboratoire de Physique des Matériaux
2 NEEL - MNM - Micro et NanoMagnétisme
3 NEEL - MRS - Matériaux, Rayonnements, Structure

New compounds corresponding to the (Ca1-xNax)(Fe2-xTix)O4 formula with 0 ≤ x ≤ 1 were prepared by solid state reactions at 1100 °C in air. A continuous solid solution was found between end members CaFe2O4 and NaFeTiO4. The evolution of structural parameters and bonding geometry with composition is discussed in detail. Magnetic measurements show that the antiferromagnetic ordering known in CaFe2O4 is suppressed for all x values investigated (x ≥ 0.2). The absence of crystallographic transition at low temperature was checked by X-ray diffraction down to 10 K. The magnetic structure of CaFe2O4 was redetermined from powder neutron diffraction. Spins on the two iron sites order antiparallel (FzFz spin arrangement), as described previously. The difference in magnetic moments on Fe1 and Fe2 sites result in a ferrimagnetic configuration with net moment 2.72 µB at 2 K.

Mots clés: oxide materials; crystal structure; magnetic measurements; neutron diffraction

Domaines: Science des matériaux [cond-mat.mtrl-sci]; Chimie inorganique

Siwar Zouari, Laurent Ranno, Abdelwaheb Cheikh-Rouhou, Olivier Isnard, Pierre Wolfers, et al.. Structural and magnetic properties of the (Ca1-xNax)(Fe2-xTix)O4 solid solution (0 x 1). Journal of Alloys and Compounds, 2008, 452 (2), pp.234-240. ⟨10.1016/j.jallcom.2007.01.074⟩. ⟨hal-00186056⟩