Influence of Dy³⁺Ions on the Microstructures and Magnetic, Electrical, and Microwave Properties of [Ni_0.4Cu_0.2Zn_0.4](Fe_2–xDy_x)O₄(0.00 ≤x≤ 0.04) Spinel Ferrites

Abstract

[Ni 0.4 Cu 0.2 Zn 0.4 ](Fe 2– x Dy x )O 4 spinel ferrite nanoparticles with different Dy 3+ concentrations (0.00 ≤ x ≤ 0.04) were prepared by a citrate sol–gel auto-combustion technique. A strong correlation among Dy concentration, structural parameters, and magnetic, electrical, and microwave properties was established. An increase in the Dy 3+ concentration is the reason for a rise in the crystal structure parameters (due to different ionic radii of Fe and Dy ions) and a slight increase in the average particle size with a minor reduction in the specific surface area. It was observed that Dy 3+ ions prefer to occupy the octahedral B site due to their large ionic radius (0.91 Å). The explanation of the electrical and magnetic properties was given in terms of the features of Dy 3+ –O 2– –Fe 3+ dysprosium–oxygen–iron indirect exchange. The occurrence of the intensive changes in amplitude–frequency characteristics was observed from 1.6 to 2.7 GHz. The explanation of electromagnetic absorption was given in terms of the peculiarities of the microstructure (resonance of domain boundaries). The results open perspectives in the utilization of [Ni 0.4 Cu 0.2 Zn 0.4 ](Fe 2– x Dy x )O 4 spinel ferrite nanoparticles as functional materials for targeted drug delivery and hyperthermia applications.

High-Performance, Lightweight, and Flexible Thermoplastic Polyurethane Nanocomposites with Zn2+-Substituted CoFe2O4 Nanoparticles and Reduced Graphene Oxide as Shielding Materials against Electromagnetic Pollution

“…The anisotropic energy of CZ3 is higher as it exhibits a lower M S value. The evaluated values of anisotropy energy are 86, 90, and 311 kOe for CZ1, CZ2, and CZ3 samples, respectively. , …”

A-Site Cation Size Effect on Structure and Magnetic Properties of Sm(Eu,Gd)Cr0.2Mn0.2Fe0.2Co0.2Ni0.2O3 High-Entropy Solid Solutions

“…Very often, in order to find materials with the required microwave parameters, it is necessary to know and optimize the anisotropic characteristics [58]. The magnetic properties of the high-entropy perovskite solid solutions obtained in this work will make it possible to select the required anisotropic parameters for the optimization of microwave materials in the future.…”

Correlation between Cation Distribution and Magnetic and Dielectric Properties of Dy3+-Substituted Fe-Rich Cobalt Ferrite

“…The large magnetostrictive effect observed in dysprosium single crystals and the maximum linear strain of λ = 7500 ppm, at low temperature (5 K), are promising . Furthermore, the substitution of larger Dy 3+ ions for smaller Fe 3+ at the octahedral site leads to increased scattering, which makes the ferrite material more resistive. , Such materials with enhanced electrical characteristics are quite useful in designing sensors for automotive applications . However, the site occupation of cations in spinel lattice is sensitive to the method of preparation, processing parameters (rate of heating, rate of cooling, sintering time, and temperature), radii of cation being substituted, etc. ,, Therefore, while rare-earth ion substitution is highly promising, precise determination of the cation distribution and establishing a correlation between the structural and electromagnetic properties are critical for their utilization in practical device applications.…”

“…The properties of lanthanide ions especially differ due to the f -electron density, which varies from element to element. , Thus, it is inspiring to explore the magnetic properties of dysprosium (Dy 3+ ) ion substituted at the Fe 3+ site in terms of the saturated magnetic moments or the f -electron density. Among all lanthanides, dysprosium ion (Dy 3+ ) has the maximum saturation magnetization value, which can be used to enhance magnetic parameters, such as saturation magnetization, remnant magnetization, etc. , Also, the relatively larger ionic size of Dy 3+ (0.912 Å) is expected to induce strain when substituted for a smaller Fe 3+ (0.64 Å) ion at the B-site. ,, Applications such as data storage require a squareness ratio close to 1 ( M r / M s ∼ 1). Stress sensitivity requires a higher rate of change of magnetization in a material as a result of the application of an external magnetic field (d M /d H ) .…”