The Néel temperature of fine particle goethite
Abstract
A sample of synthetic fine particle goethite has been been studied using neutron diffraction, Mössbauer spectroscopy and magnetisation measurements. The three methods yield a consistent magnetic ordering temperature of 358(1) K. It is concluded that the goethite particles in the sample are not superparamagnettic or "superferromagnetic"; rather the Néel temperature is lower than that of well-crystallized goethite. The reduced Néel temperature is attributed to the presence of vacancy defects in the particles. The saturation magnetic moment obtained from the neutron diffraction measurements was 3.80(2)μ B per iron atom.
- Publication:
-
Journal of Magnetism and Magnetic Materials
- Pub Date:
- March 1992
- DOI:
- 10.1016/0304-8853(92)91758-L
- Bibcode:
- 1992JMMM..109..260B