Mossbauer effect study of Ni1-xCuxMnyFe2-yO4 system

The Mossbauer effect technique has been employed for the study of magnetic properties of spinel series Ni1-xCuxMnyFe2-yO4 with 0.0 less than or equal tox less than or equal to1.0, and y=0.6. The substitution of Mn3+ and Cu2ions results in a slight decrease of the hyperfine field at B- as well as A -sites. The area ratio of Fe3+ ions at the A- and B-site at 77 K indicates that Cu2+, Ni2+ and Mn3+ ions occupy the octahedral sites in an evidence fo r complete inverse spinel in this system. The temperature dependence of the hyperfine parameters has been studied for composition with x=0.5 where Nee l point T-N and Debye temperature theta (D) are found to be 650 and 679 K, respectively. The temperature dependence of the sublattice magnetization si gma (T) obeys a one-third-power law in the range 0.5 <T/T-N<0.99.