https://doi.org/10.1007/s100510050269
Magnetic resonance in oxygen-doped La2NiO4+8
1
Centre de Recherches sur la Physique des Hautes
Températures, CNRS, 45071 Orléans Cedex 2, France
2
ICMCB, CNRS, 33608 Pessac Cedex, France
Corresponding author: a odier@cnrs-orleans.fr
Received:
3
November
1997
Accepted:
23
December
1997
Published online: 15 April 1998
We report an investigation of magnetic resonance by ESR in
oxygen-doped La2NiO4+8
emphasizing extensively for the first time the role of oxygen stoichiometry. The work is
performed at room temperature and on powders
with 
. At low field an hysteresis
is detected between increasing and decreasing fields, it
depends upon δ. The resonance lines
have characteristic features of ferromagnetic resonance. The
intensity (
) is used as an
experimental parameter for investigating the effect of δ.
It allows to built a diagram closely
connected to the phase diagram 
. It suggests a ferromagnetic
coupling depending upon δ.
When the (average) structure is tetragonal the low intensity is due to a magnetic polaron of
low resistivity. In ranges where a phase separation is detected, the ferromagnetic coupling has
a structural origin (DM or local anisotropy) with apparently a strong influence on the electrical
resistivity.
PACS: 72.80.-r – Conductivity of specific materials / 75.80.+q – Magnetomechanical and magnetoelectric effects, magnetostriction / 76.50.+g – Ferromagnetic, antiferromagnetic, and ferrimagnetic resonances; spin-wave resonance
© EDP Sciences, Società Italiana di Fisica, Springer-Verlag, 1998
