Mossbauer studies on exchange interactions in CoFe2O4

Citation
Sj. Kim et al., Mossbauer studies on exchange interactions in CoFe2O4, JPN J A P 1, 40(8), 2001, pp. 4897-4902
Citations number
20
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Apllied Physucs/Condensed Matter/Materiales Science
Volume
40
Issue
8
Year of publication
2001
Pages
4897 - 4902
Database
ISI
SICI code
0021-4922(200108)40:8<4897:MSOEII>2.0.ZU;2-9
Abstract
Two polycrystalline samples of CoFe2O4 were prepared by slow cooling and qu enching and studied using Mossbauer spectroscopy and X-ray diffraction. The crystals were found to have a cubic spinet structure with the lattice cons tants of the slowly cooled sample being a(0) = 8.381 Angstrom and the quenc hed sample being a(0) = 8.391 Angstrom. The temperature dependence of the m agnetic hyperfine field in Fe-57 nuclei at the tetrahedral (A) and octahedr al (B) sites was analyzed based on the Neel theory of ferrimagnetism. For t he slowly cooled sample, the intersublattice A-B superexchange interaction and intrasublattice A-A superexchange interaction were anti ferromagnetic w ith a strength of J(A-B) = -25.0 k(B) and J(A-A) = - 18.9k(B), respectively , while the intrasublattice B-B superexchange interaction was ferromagnetic with a strength of J(B-B) = 3.9 k(B). In the quenched sample, however, the ir strengths were J(A-B) = -22.6 k(B), J(A-A) = - 17.6 k(B), and J(B-B) = 3 .9 k(B), respectively.