RT journal article
T1 Magnetic fluctuations in nanosized goethite (α-FeOOH) grains
A1 Madsen, D E
A1 Cervera Gontard, Lionel
A1 Kasama, Takeshi
A1 Dunin-Borkowski, Rafal E
A1 Koch, C B
A1 Hansen, M F
A1 Frandsen, C
A1 Mørup, S
A2 Física de la Materia Condensada
AB Mo¨ssbauer spectra of antiferromagnetic goethite (α-FeOOH) particles usually show an asymmetric line broadening, which increases with increasing temperature, although the magnetic anisotropy is expected to be so large that magnetic relaxation effects should be negligible. By use of high resolution transmission electron microscopy we have studied a sample of goethite particles and have found that the particles contain many defects such as low angle grain boundaries, in accordance with previous studies of other samples of goethite particles. Such defects can result in a magnetic mismatch at the grain boundaries between nanometer-sized grains, leading to a weakened magnetic coupling between the grains. We show that the Mo¨ssbauer data of goethite can be explained by fluctuations of the sublattice magnetization directions in such weakly coupled grains. It is likely that the influence of defects such as low angle grain boundaries also plays a role with regards to the magnetic properties in other antiferromagnetic nanograin systems. We discuss the results in relation to Mo¨ssbauer studies of α-Fe2O3 and α-Fe2O3/NiO nanoparticles.
PB IOP
SN 0953-8984
YR 2009
FD 2009
LK http://hdl.handle.net/10498/35022
UL http://hdl.handle.net/10498/35022
LA eng
DS Repositorio Institucional de la Universidad de Cádiz
RD 15-nov-2026