Characteristic length scales of nanosize zinc ferrite

Abstract

Nanosize zinc ferrite samples with an average particle size of 6–65 nm were prepared by a new chemical reaction involving nitrates of Zn and Fe and investigated for magnetic behaviour and defect structure. The sample with an average particle size of 6 nm has considerable inversion in cation distribution as shown by its hysteresis loop and increased magnetization. Mössbauer spectroscopy gives a single doublet for all the samples. Mössbauer parameters like quadrupole splitting and linewidth change sharply as the average particle size increases from 6 to 7 nm and then afterwards the changes are slow. The total Mössbauer absorption, on the average, increases with increase in particle size, the change from 6 to 65 nm being by a factor of 3. Positron parameters too change sharply as the particle size varies. The changes are related to inversion of the cation distribution, agglomeration of particles and annihilation at the surface and in the interior. The picture that emerges from the lifetime studies and supported by Mössbauer spectroscopy and magnetization studies suggests that there are at least two characteristic particle size length scales for nanosize ZnFe2O4 particles prepared by the nitrate route.

Effect of Preparation on Structure and Magnetic Properties of ZnFe2O4

“…In agreement with previous studies [17,18] we observed that the absorption area increases for ZM and ZS compare to that of ZC. It is well known that area of the curve is a measure of recoil free fraction.…”

Resistivity dependent dielectric and magnetic properties of Pb(Fe0.012Ti0.988)O3 nanoparticles

“…Nanosized magnetoelectric material causes superparamagnetic relaxation contribute to least the hysteresis than ferromagnetic. 29 The enhancement in ferromagnetic properties is due to the smaller particle size in our specimen.…”

An Overview on Nanocrystalline ZnFe2O4, MnFe2O4, and CoFe2O4 Synthesized by a Thermal Treatment Method

“…But, due to the degree of inversion, which is large for smaller size particles, intersublattice (A-B) super-exchange interactions in smaller size particles occur to a greater extent than in larger size particles. Hence, saturation magnetization increases for smaller size particles [31], using Mossbauer's experiment, showed that the degree of inversion is large in the case of smaller size particles. Also, an impure α-Fe 2 O 3 phase was detected by XRD (Figure 2(a)), the heating rate of calcinations and the surface spin structure can be an influence that increases the saturation magnetization in smaller size particles [18].…”