SURFACE EFFECT ON THE MORIN TRANSITION OF ALPHA-FE2O3 PARTICLES COATED WITH SURFACTANT

Citation
L. Kumar et al., SURFACE EFFECT ON THE MORIN TRANSITION OF ALPHA-FE2O3 PARTICLES COATED WITH SURFACTANT, Hyperfine interactions, 84(1-4), 1994, pp. 137-141
Citations number
7
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Physics, Atomic, Molecular & Chemical","Physics, Nuclear","Physics, Condensed Matter
Journal title
ISSN journal
0304-3843
Volume
84
Issue
1-4
Year of publication
1994
Pages
137 - 141
Database
ISI
SICI code
0304-3843(1994)84:1-4<137:SEOTMT>2.0.ZU;2-X
Abstract
Uniform hematite particles with an average size of 400 angstrom were p repared for reducing the influence of the particle-size distribution o n the measurement of the Morin temperature. A series of Mossbauer spec tra at different temperatures have been recorded. The Morin transition occurs at 216 K for sample B coated with a surfactant-oleic acid, and it occurs at 192 K for uncoated sample A. The temperature intervals i n the region of the spin flip are almost the same for both samples. Th ese results show that a T(m) shift could arise from surface effects su ch as spin pinning directly induced by a surfactant, and that the dist ortion produces restriction not only on the top few layers, but also o n the whole volume of the particle.