Effects of Mg substitution on the structural and magnetic properties of Co _0.5 Ni _{0.5− x} Mg _x Fe ₂ O ₄ nanoparticle ferrites

Abstract

In this study, nanocrystalline Co-Ni-Mg ferrite powders with composition Co 0.5 Ni 0.5−x Mg x Fe 2 O 4 are successfully synthesized by the co-precipitation method. A systematic investigation on the structural, morphological and magnetic properties of un-doped and Mg-doped Co-Ni ferrite nanoparticles is carried out. The prepared samples are characterized using x-ray diffraction (XRD) analysis, Fourier transform infrared spectroscopy (FTIR), field emission scanning electron microscopy (FESEM), and vibrating sample magnetometry (VSM). The XRD analyses of the synthesized samples confirm the formation of single-phase cubic spinel structures with crystallite sizes in a range of ∼ 32 nm to ∼ 36 nm. The lattice constant increases with increasing Mg content. FESEM images show that the synthesized samples are homogeneous with a uniformly distributed grain. The results of IR spectroscopy analysis indicate the formation of functional groups of spinel ferrite in the co-precipitation process. By increasing Mg 2+ substitution, room temperature magnetic measurement shows that maximum magnetization and coercivity increase from ∼ 57.35 emu/g to ∼ 61.49 emu/g and ∼ 603.26 Oe to ∼ 684.11 Oe (1 Oe = 79.5775 A•m −1 ), respectively. The higher values of magnetization M s and M r suggest that the optimum composition is Co 0.5 Ni 0.4 Mg 0.1 Fe 2 O 4 that can be applied to high-density recording media and microwave devices.

Enhancement of Viscoelastic and Electrical Properties of Magnetorheological Elastomers with Nanosized Ni-Mg Cobalt-Ferrites as Fillers

“…As shown in Figure 3a,b, the A1 and A2 samples exhibit spherical shapes and the nanoparticles are clearly aggregated, which is likely due to strong Van der Waals or magnetostatic interactions between bigger nanoparticles (promoted by the sintering process), a phenomenon which has been reported in previous research by Rosnan et al [37]. In addition, by using the J-image software, the mean particle sizes observed were in the range of 35 to 80 nm.…”

“…The conventional co-precipitation method was used to synthesize the nanosized Ni-Mg cobalt ferrites, namely Co 0.5 Ni 0.2 Mg 0.3 Fe 2 O 4 (A1) and Co 0.5 Ni 0.1 Mg 0.4 Fe 2 O 4 (A2). The procedures for the synthesized MRE samples, A1 and A2, were based on the previous method reported by Rosnan et al [37]. The stoichiometric molar amounts of Ni(NO 3 ) 2 ∙6H 2 O, Mg(NO 3 ) 2 ∙6H 2 O, Co(CH 3 COO) 2 ∙4H 2 O and Fe(NO 3 ) 3 ∙9H 2 O were introduced.…”

“…It should be noted that to the best of our knowledge, MRE with the nanosized Ni-Mg cobalt ferrites as a filler has never been reported, despite several benefits of the proposed filler. For example, the nanosized Ni-Mg cobalt ferrites exhibit high magnetic remanence and large surface activities [37]. Their properties are believed to demonstrate better magnetic, rheological, as well as electrical properties of MRE.…”

Structural, Magnetic, and Catalytic Evaluation of Spinel Co, Ni, and Co–Ni Ferrite Nanoparticles Fabricated by Low-Temperature Solution Combustion Process

“…35 In fact, reports on the fabrication of stoichiometric Co 0.5 Ni 0.5 Fe 2 O 4 NPs in pure spinel phase have been scarce in the literature. Co 0.5 Ni 0.5 Fe 2 O 4 NPs have been fabricated through co-precipitation at solution pH 13, with further annealing at 900 °C for 10 h. 36 Poly(vinyl alcohol)-assisted sol–gel method has also been used to fabricate Co 0.5 Ni 0.5 Fe 2 O 4 NPs. However, the quality of those NPs could not be guessed as their morphological and spectroscopic results were not reported.…”

“…Although the magnetic properties of spinel cobalt and nickel ferrites have been studied by several research groups, 3,8,13,24,21,38,39 there exist very few reports in the literature on the magnetic properties of Co 0.5 Ni 0.5 Fe 2 O 4 NPs, especially beyond room temperature. 28,36 Furthermore, although Rosnan et al reported a coercivity field ( H c ) of 603.26 Oe for their Co 0.5 Ni 0.5 Fe 2 O 4 NPs fabricated by co-precipitation and postgrowth sintering at 900 °C for 10 h, 36 Raju et al reported a H c value of just 250 Oe for their Co 0.5 Ni 0.5 Fe 2 O 4 NPs fabricated by the citrate mediated sol–gel method. As the H c value is a critical parameter for possible magnetic applications of this ferrite, it is worth to synthesize and study the magnetic properties of Co 0.5 Ni 0.5 Fe 2 O 4 NPs in comparison with phase-pure spinel CoFe 2 O 4 and NiFe 2 O 4 NPs fabricated under identical synthesis conditions.…”