Berlin 2012 – wissenschaftliches Programm
MA 27.8: Vortrag
Mittwoch, 28. März 2012, 11:30–11:45, EB 202
Cation distributions and its influence on magnetostrictive properties in inverse spinel ferrites CoFe2O4 and NiFe2O4 — •Daniel Fritsch and Claude Ederer — School of Physics, Trinity College Dublin, Ireland
Spinel ferrites CoFe2O4 (CFO) and NiFe2O4 (NFO) are both insulating ferrimagnetic oxides with a high magnetic ordering temperature and large saturation magnetisation. Moreover, CFO is a highly magnetostrictive material, i.e., it shows a large length change when exposed to a magnetic field.
The spinel structure consists of two magnetic sublattices, namely A- and B-sublattice, which in the normal spinel structure are solely occupied by one of the two cation species. An increasing exchange between the two cation species leads to the inverse spinel structure where two cation species are distributed over the B-sublattice. These different possible cation distributions over the B-sublattice strongly influence the total energy of these materials .
It has already been shown that density functional theory (DFT) calculations together with the Hubbard “+U” approach provide reliable insight in the structural and magnetic properties of these materials . Here we present DFT total energy calculations for CFO and NFO with different possible cation distributions over the B-sublattice and their influence on the magnetostrictive properties. These results are compared to available experimental data.
 D. Fritsch and C. Ederer, Appl. Phys. Lett. 99, 081916 (2011).
 D. Fritsch and C. Ederer, Phys. Rev. B 82, 104117 (2010).