Hyperfine field and relaxation effect in Li−Zn−Ti ferrites

Abstract

57Fe Mossbauer effect studies were made on titanium substituted Li−Zn ferrite with composition Li0.45+0.5tZn0.1 Tit Fe2.45–1.5tO4 (t=0.0 to 1.2) at 300K. The Mossbauer spectra for t≤0.4 show two well defined Zeeman sextets corresponding to the Fe3+ ions at tetrahedral (A) and octahedral (B) sites. The spectra for t=0.6, 0.8 and 0.9 show relaxation but can still be resolved into 2 sextets. The spectra for t=1.0, 1.2 show strong ferrimagnetic relaxation with the spectra for t=1.2 exhibiting an additional central doublet. The effect of Ti4+ substitution on the Isomer shift (I.S), Quadrupole splitting (Q.S.) and nuclear magnetic fields of Li−Zn ferrites have been reported in this paper. The I.S. was found to be independent of substitution level t, while the quadrupole splitting was observed to be negligible. The variation of hyperfine field with t has been explained on the basis of superexchange interaction and cation distribution.