Role of Ruthenium in the Dielectric, Magnetic Properties of Nickel Ferrite (Ru–NiFe₂O₄) Nanoparticles and Their Application in Hydrogen Sensors

Abstract

In this work, Ru-doped nickel ferrites (NiFe 2 O 4 ) were synthesized by a chemical co-precipitation method. Subsequently, they were annealed at different temperatures. The crystallinity of the samples was evaluated using X-ray diffraction and the morphology of the samples was investigated by scanning electron microscopy and transmission electron microscopy. Dielectric constants and dielectric loss were studied. Ru-doped nickel ferrite samples showed relatively low dielectric constant and loss. Also, the dielectric constant and loss decreased with increasing annealing temperature. Vibrational sample magnetometer analysis shows the hysteresis loop of a soft magnetic nature and the relevant parameters ( M r, M s and H c ) have low values that confirmed the nature of the material. Subsequently, gas sensors were fabricated to study hydrogen-sensing properties. The gas sensors showed a response to hydrogen gas at a low temperature (100 °C) with selective response in the presence of NH 3 and C 2 H 5 OH gases. The reasons for electrical, magnetic, and sensing behavior of the samples were discussed in detail.

Tunable Dielectric Properties of Nickel Ferrite Derived via Crystallographic Site Preferential Cation Substitution

“…Nickel ferrite offers numerous ways to obtain desirable properties and/or tailor the structure and properties at the nanoscale dimensions, although researchers often aim at achieving tunable magnetic and electrical properties. − Apart from variable synthetic procedures, strategies, and processing conditions, metal-ion doping is one of the promising routes to achieve desirable properties in NFO. − Typically, the dopant ionic size must be comparable to the size of metal cation (Ni or Fe in NFO), resulting in the formation of a well-defined solid solution, without any secondary phases. In addition to the size of the dopant ion, the nature (magnetic or nonmagnetic), crystallographic site preference (A-site or B-site), amount of substitution (lower or higher), and ionic charge (chemical valence state) of the dopant ion are also crucial parameters in tuning the properties of the parent NFO compound.…”

“…A wealth of information is available in the literature, where various dopant-induced effects on the structure and properties of nickel ferrites are evident. − Also, plenty of reports are available on the dielectric properties of nanocrystalline NFO and doped NFO. − However, based on the studies available in the literature and the aforementioned structural details, it is quite important to understand the effect of crystallographic site preference of the cations on the magnetic and electrical properties. Specifically, a comparative study of the metal cations with the same composition but different site preferences in NFO can provide clues to manipulate the properties and performance.…”

NiFe2O4 Nanoparticles Synthesized by Dextrin from Corn-Mediated Sol–Gel Combustion Method and Its Polypropylene Nanocomposites Engineered with Reduced Graphene Oxide for the Reduction of Electromagnetic Pollution

“…13,14 Nickel ferrite (NiFe 2 O 4 ) is one of the important candidates among the spinel ferrite family because of its application in microwave, electronic, magnetic, and electrochemical devices. 15 It exhibits a low coercivity, eddy and hysteresis loss; therefore, it is beneficial for electronic devices such as telecommunications and high-frequency devices. 16 It has been also noticed that the electromagnetic wave absorption capability of spinel ferrite nanoparticles depends on its structural characteristics such as crystallinity, particle size, cation distribution, morphology, dopant ions, etc.…”

“…Therefore, the physical characteristics of nanocomposites could be improved by the optimization of microstructure. It is of great interest to investigate the impact of microstructure on the electromagnetic interference shielding characteristics. , Spinel ferrite nanoparticles have received a great potential in the wide range of applications such as information storage, electronic devices to medical diagnostics, drug delivery, supercapacitors, anode materials for lithium-ion batteries, and microwave- and radar-absorbing material. , Nickel ferrite (NiFe 2 O 4 ) is one of the important candidates among the spinel ferrite family because of its application in microwave, electronic, magnetic, and electrochemical devices . It exhibits a low coercivity, eddy and hysteresis loss; therefore, it is beneficial for electronic devices such as telecommunications and high-frequency devices .…”

Fast and Efficient Removal of Uranium onto a Magnetic Hydroxyapatite Composite: Mechanism and Process Evaluation

“…To effectively recover the adsorbed material and maintain the stability of the target material, nano CoFe 2 O 4 and HAP can be coupled through a facile hydrothermal process. The as-synthesized HAP@CoFe 2 O 4 exhibits superior composition uniformity, narrow particle size distribution, and can be therefore magnetically separated from reaction systems [39]. To the best of our knowledge, the use of a rationally designed HAP@CoFe 2 O 4 composite as a sorbent to abate and fix U(VI) has been rarely reported.…”