Structure induced tunable magnetic properties of Zn substituted Mn_1−xZn_xFe₂O₄(x= 0–1) NPs

Abstract

Mn 1−x Zn x Fe 2 O 4 nanoparticles (MZ NPs) owing to their Zn content dependent tunable magnetic properties have potential applications in energy conversion devices and in nanomedicine. It is a well-recognised fact that magnetism of MZ NPs has critical dependence on degree of Zn substitution at tetrahedral sites. In addition, the role of cation distribution between the tetrahedral and octahedral sites for a particular degree of Zn-substitution, i.e. the degree of inversion (δ) also influences their magnetic characteristics. However, the exact correlation between distribution of bivalent metal ions between tetrahedral and octahedral sites and corresponding magnetic characteristics is not well understood. In order to explore this structural dependence of magnetic characteristics of MZ NPs, a series of Mn 1−x Zn x Fe 2 O 4 (x = 0−1) nanoparticles have been synthesized by chemical co-precipitation method. Saturation magnetisation and Curie temperature of MZ NPs are strongly correlated with the degree of inversion and exchange interactions between the magnetic ions, while the coercivity and remanence is independent of it and only depends on crystallite size. Both saturation magnetisation and Curie temperature decreases with increasing Zn substitution into spinel matrix. This could be attributed to the weakening of strong (A-B) inter lattice super exchange interaction instead partial substitution of Zn at octahedral Mn sites.

Fabrication of Mn1Zn Fe2O4 ferrofluids from natural sand for magnetic sensors and radar absorbing materials

“…For the maximum Mn ion composition, the lattice parameters and crystal volume increased significantly and decreased gradually with the increasing Zn ion composition. The crystal structure of the samples was similar to a previous study [ 22 ]. In this work, all samples had a spinel cubic structure [ 23 ], where the Mn 2+ , Zn 2+ , Fe 2+ , and Fe 3+ were randomly in octahedral and tetrahedral sites in the spinel system with lattice parameters of a = b = c .…”

“…Kaur et al. explained that the saturation magnetization of magnetic nanoparticles in the spinel system depends on their magnetic moment and exchange interaction [ 22 ]. In the spinel structure, the magnetic moment is influenced by the atomic spin interaction mechanism at the A-site and B-site.…”

Colloidal stability of Mn 1− x Zn x Fe 2 O 4 nanoparticles in transformer oil: role of Zn substitution

“…Depending on the operating temperature requirement of the transformer, the degree of Zn substitution can be chosen. For example, we have reported the highest Curie temperature (652 K) for MZ0 fluids [13], which can be utilised for cooling of transformers having an operating temperature of 380°C.…”

“…To prepare magnetic fluids, NPs of MZ ( x = 0–1) were prepared by the co‐precipitation method by following the protocols reported previously [13]. Oleic acid was used to coat magnetic NPs [14].…”

“…In our previous work, we have reported the synthesis of MZ NPs series by the coprecipitation method with tunable magnetic properties [13]. In this Letter, a detailed discussion on the development of synthesis protocols for MZ fluids is described.…”