Adhesive and viscoelastic performance of surface functionalized nano‐Fe3O4 induced orientated ethylene vinyl‐acetate composite hot melt adhesives

Different surface functionalized Fe₃O₄ were added to ethylene vinyl‐acetate copolymers (EVA) composite hot melt adhesives (HMAs) to study their influence on the properties of composite HMAs. The adhesion and viscoelastic properties for HMAs were studied using an electromechanical universal testing machine, dynamic mechanical analyzer (DMA) and parallel‐plate rheometer, respectively. Orientation structure of HMAs was studied by Infrared dichroism. The results showed that tetraethoxysilane (TEOS) treated Fe₃O₄ showed better compatibility with EVA composite HMAs, and that TEOS‐treated Fe₃O₄/EVA composite HMAs presented better adhesion property and processing fluidity, compared with bare Fe₃O₄/EVA composite HMAs and silane coupling agent KH560 treated Fe₃O₄/EVA composite HMAs. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43931.     

Single step modification of micrometer-sized polystyrene particles by electromagnetic polyaniline and sorption of chromium(VI) metal ions from water

This article describes a single-step reproducible approach for the surface modification of micrometer-sized polystyrene (PS) core particles to prepare electromagnetic PS/polyaniline–Fe₃O₄ (PS/PANi–Fe₃O₄) composite particles. The electromagnetic PANi–Fe₃O₄ shell was formed by simultaneous seeded chemical oxidative polymerization of aniline and precipitation of Fe₃O₄ nanoparticles. The weight ratio of PS to aniline was optimized to produce core–shell structure. PS/PANi–Fe₃O₄ composite particles were used as adsorbent for the removal of Cr(VI) via anion-exchange mechanism. The composite particles possessed enough magnetic property for magnetic separation. The adsorption was highly pH dependent. Adsorption efficiency reached 100% at pH 2 in 120 min when 0.05 g of composite particles was mixed with 30 mL 5 mg L⁻¹ Cr(VI) solution. The adsorption isotherm fitted best with Freundlich model and maximum adsorption capacity approached 20.289 mg g⁻¹ at 323 K. The prepared composite was found to be an useful adsorbent for the removal of soluble Cr(VI) ions. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 47524.     

A review of the structure,magnetic and electrical properties of bismuth ferrite (Bi2Fe4O9)

Nowadays, investigations on the materials with multiferroic properties are in progress. These materials compromise simultaneous electric and magnetic properties. Ferrite Bismuth (FB) is one of the ceramic materials that enjoy this property and possesses three different crystalline structures (perovskite BiFeO₃, selenite Bi₂₅FeO₄₀ and mullite Bi₂Fe₄O₉). In this review, first, the crystalline structure and the electric and magnetic properties of Bi₂Fe₄O₉ are studied, and then, the effects of adding dopants to the ferrite are discussed. Mullite-type bismuth ferrite (Bi₂Fe₄O₉) as a spin frustrated multiferroic has potential for magnetoelectric coupling, and it might be an appropriate alternative for some of the multiferroics that suffer from a weak magnetoelectric coupling.     

Fabrication and characterization of the orientated MMT/PI composite films via relatively low magnetic field

Anisotropic cetylpyridinium modified magnetic montmorillonite/polyimide (CPC‐Fe₃O₄‐MMT/PI) composite films were prepared based on CPC‐Fe₃O₄‐MMT capable of exfoliation and magnetic‐field response via in situ polymerization and relatively low magnetic field adjustment (0.6 T) in the film casting followed by imidization. The stability of CPC‐Fe₃O₄‐MMT during the in situ polymerization over flow shearing of the polymers and longtime stirring was evaluated by comparison the composition of CPC‐Fe₃O₄‐MMT before and after polymerization via TG analysis and element analysis. Besides, the structural anisotropy of the produced CPC‐Fe₃O₄‐MMT/PI composite films deriving from orientation of plate‐like CPC‐Fe₃O₄‐MMT was confirmed by 1‐D and 2‐D XRD and SEM. The CPC‐Fe₃O₄‐MMT/PI composite films with structural anisotropy exhibit gas permeation, optical and magnetic anisotropic properties which would widen the application fields of the composite films. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 41224.     

Multiferroic ceramics in BaO–Y2O3–Fe2O3–Nb2O5 system

Multiferroic ceramics in BaO–Y₂O₃–Fe₂O₃–Nb₂O₅ system were synthesized and their dielectric, ferroelectric and magnetic properties were evaluated. XRD results showed that the ceramic composite consists of a major phase of tetragonal tungsten bronze structured Ba₂YFeNb₄O₁₅, and minor phases of monoclinic YNbO₄ and hexagonal Ba₃Fe₂Nb₆O₂₁. Three dielectric relaxations were observed in the temperature range from 125 to 575 K. The relaxor dielectric behavior in the temperature range from 125 to 350 K was attributed to the random occupation of Fe³⁺ and Nb⁵⁺ ions at B site of the tungsten bronze structure. The electrode polarization and the inhomogeneous structure contributed to the high-temperature and middle-temperature dielectric relaxations, respectively. Both the ferroelectric hysteresis loop and the magnetic hysteresis loop were measured, which suggested that the synthesized ceramic composite was a promising candidate of multiferroics.     

Cr(III)‐containing Fe3O4/mercaptopropanoic acid‐poly(2‐hydroxyethyl acrylate) nanocomposite: Highly active magnetic catalyst for direct hydroxylation of benzene

In this study, polymer‐grafted magnetic nanoparticles containing chromium(III) ions incorporated onto Fe₃O₄/mercaptopropanoic acid‐poly(2‐hydroxyethyl acrylate) was prepared via a simple and in situ method. The obtained magnetic nanocomposite exhibited high catalytic activity and excellent selectivity in direct hydroxylation of benzene in the presence of hydrogen peroxide under solvent‐free condition. The magnetic catalyst could be also separated by an external magnet and reused seven times without any significant loss of activity/selectivity. Due to the Lewis acidity of the Fe³⁺ groups in the structure of magnetic nanoparticles, the high efficiency of this catalyst is possibly due to the synergetic effect of Cr³⁺ and Fe³⁺ groups in the structure of magnetic nanocomposite. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40383.     

Mussel‐inspired magnetic adsorbent: Adsorption/reduction treatment for the toxic Cr(VI) from simulated wastewater

A novel magnetic adsorbent, poly(catechol‐1,4‐butanediamine)‐coated Fe₃O₄ composite (Fe₃O₄@PCBA), was successfully fabricated via an easy and gentle method according to the mussel‐inspired adhesion property of polydopamine. Effects of many factors on the adsorption performance of Fe₃O₄@PCBA for Cr(VI) were investigated, including temperature, pH value, contacting time, adsorbent dosage, and initial Cr(VI) concentration. The thermodynamics, adsorption isotherm, kinetics, and intraparticle diffusion of adsorption were also studied systematically. Results indicated that the removal rate of Cr(VI) was approximately close to 100% when the initial concentration was less than 120 mg/L, and the maximum uptake capacity of Fe₃O₄@PCBA for Cr(VI) was 280.11 mg/g complied with Langmuir isotherm model. Accordingly, the nocuous Cr(VI) could be partially reduced to Cr(III) during the adsorption period. Hopefully, this strategy could be extended to prepare series of magnetic Fe₃O₄@catechol–amine adsorbents with different amino and phenolic hydroxyl groups for Cr(VI) removal. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 46530.     

Retention of Pb(II) by a Low-Cost Magnetic Composite Prepared by Environmentally-Friendly Plasma Technique

A low-cost magnetic composite (gelatin/Fe₃O₄) is prepared by Fe₃O₄ nanoparticles treated with gelatin using an environmentally-friendly plasma technique, and is applied for the removal of toxic Pb(II) ions from aqueous solutions. Not only that it originates from cheap and abundant raw materials, the gelatin/Fe₃O₄ composite also has advantages in convenient magnetic separation from aqueous solution, which can hopefully reduce water treatment expenses. The batch experimenta results indicate that the maximum adsorption capacity (q_max) of Pb(II) on this gelatin/Fe₃O₄ composite is ～115 mg/g, higher than most of the other bare and modified magnetic materials, which is considered to be attributed to the strong interaction between Pb(II) and the abundant functional groups introduced by gelatin. When exposed to acidic solutions, the dissolution of the gelatin/Fe₃O₄ nanoparticles is minimal due to the protective character of the grafted gelatin layer on the Fe₃O₄ nanoparticles. The utilization of the plasma technique in the synthesis of magnetic composite agrees well with the tenet of green chemistry. It is promising that this gelatin/Fe₃O₄ composite would become an efficient and economic material for heavy metal ion removal in the practical environmental remediation.     

Fabrication and characterization of polymer composites surface coated Fe3O4/MWCNTs hybrid buckypaper as a novel microwave‐absorbing structure

A naval hybrid buckypaper was fabricated by vacuum filtration method with monodispersion solution of Fe₃O₄ decorated Multiwalled carbon nanotubes (MWCNTs). The morphology, element composition and phase structure of hybrid buckypaper were characterized by field‐emission scanning electron microscope, energy dispersive spectrometer, and X‐ray diffraction. The microwave absorption and complex electromagnetic properties of the composites surface coated MWCNTs buckypaper (or Fe₃O₄/MWCNTs hybrid buckypaper) have been investigated in the frequency range of 8–18 GHz. The results indicate that the microwave absorption properties of composite structure have been evidently improved due to the Fe₃O₄/MWCNTs hybrid buckypaper' high magnetic loss and suitable dielectric loss properties. The reflection loss of composite surface coated Fe₃O₄/MWCNTs hybrid buckypaper (with a matching thickness d = 0.1 mm) is below ?10 dB in the frequency range of 13–18 GHz, and the minimum value is ?15.3 dB at 15.7 GHz. Thus, Fe₃O₄/MWCNTs hybrid buckypaper can become a promising candidate for electromagnetic‐wave‐absorption materials with strong‐absorption, thin‐thickness and light‐weight characteristics. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 41974.     

Microstructural and multiferroic properties in layered perovskite-related Sm6Ti4Fe2O20

Layered perovskite-related Sm₆Ti₄Fe₂O₂₀ compound was successfully synthesized through the intercalation of bilayer SmFeO₃ into the Sm₂Ti₂O₇ with pyrochlore structure by means of floating-zone melting technique. The microstructural properties were characterized using aberration-corrected scanning transmission electron microscopy and X-ray diffraction. Electron energy-loss spectroscopy investigation reveals that the Fe³⁺ ions prefer to occupy the inner sites within the perovskite-like layers. This compound exhibits clearly the spin glass-like behavior as demonstrated by the magnetic properties measurement. Such complex magnetic behavior could be attributed to the partial chemical order of Ti/Fe over the B sites and the interactions between magnetic ions including Sm³⁺ and Fe³⁺. In addition, the multiferroic behavior with the coexistence of the ferroelectricity and ferromagnetism was well established by magnetic and piezoresponse measurements.     

Preparation of molecularly imprinted Fe3O4/P(St‐DVB) composite beads with magnetic susceptibility and their characteristics of molecular recognition for amino acid

Tyrosine and phenylalanine imprinted Fe₃O₄/P(St‐DVB) composite beads with magnetic susceptibility were prepared by suspension polymerization using Fe₃O₄ as the magnetically susceptible component, methacrylic acid and acrylamide as functional monomers, styrene and divinylbenzene as polymeric matrix components, stearic acid as porogen, and poly(ethylene glycol) 4000 as dispersant. Scanning electron microscopy examination of the composite beads showed macropores on the surface of spherical beads. The diameters of the composite beads and the macropores were in the ranges ～ 400–450 and 4–20 μm, respectively. The average content of Fe₃O₄ inside the composite beads was 3.78%, and Fe₃O₄ was unevenly distributed. The mechanism of macropore formation and the concept of “intellectual cavity” of molecularly imprinted composite beads were proposed. The recognition selectivity of the composite beads was investigated using tyrosine and phenylalanine as both templates and comparative molecules. Tyrosine‐imprinted composite beads exhibited a good recognition selectivity for tyrosine, and the separation factor was up to 3.67. In contrast, phenylalanine‐imprinted composite beads had little recognition selectivity for phenylalanine and the separation factor was only 1.12. It was confirmed that the three‐site interaction between tyrosine and functional monomers was stronger than the two‐site interaction between phenylalanine and functional monomers. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 3790–3796, 2003     

Facile synthesis of La-doped cobalt ferrite@glucose-based carbon composite as effective multiband microwave absorber

C/CoLa_xFe_2−xO₄ (with x = 0.1, 0.2, 0.3) composites were compounded by using a high-temperature hydrolysis. X-ray Diffraction (XRD) and X-ray Photoelectron Spectroscopy (XPS) results show that doping of La ions does not alter the spinel crystal structure and partially replaces Fe ions. Results of Field-Emission Scanning Electron Microscope (FESEM) and Energy Dispersive Spectroscopy (EDS) mapping prove that with the doping of La ions, the grains are refined, and the carbon shell on the surface exists. The effect of doping of La ions on microwave absorption performance of the composites was systematically studied. It is found that an optimal reflection loss (RL) of −49.56 dB is achieved at 4.96 GHz, as the composition is C/CoLa_0.2Fe_1.8O₄. Meanwhile, the sample C/CoLa_0.3Fe_1.7O₄ shows excellent effective absorption bandwidth. Specifically, when the matching thicknesses are 4 and 5 mm, the effective absorption bandwidth is 4 GHz, covering the C band and Ku band, thus realizing multiband absorption. The synergistic effects of the enhanced dipole polarization related to the doping of La ions, improved interface polarization of the core-shell structure, and the magnetic loss originated from CoLa_xFe_2−xO₄ are responsible for the optimal microwave absorption performance. Therefore, this C/CoLa_xFe_2−xO₄ composite material has the prospect of a multiband high-efficiency microwave absorber.     

Interfacial and mechanical properties of γ‐Fe2O3/segmented polyurethane/poly(vinyl chloride) composites

Segmented polyurethane (SPU)/poly(vinyl chloride) (PVC) blends were particulated with γ‐Fe₂O₃. Interfacial properties of the composite were studied through the adsorption behaviors of SPU and PVC and their blends on γ‐Fe₂O₃ particles surface. Mechanical properties of the composite were measured with dynamic mechanical analysis and tensile test measurements. PVC with functional groups (FPVC), because of strong interactions, showed preferential adsorption on γ‐Fe₂O₃ compared with SPU and PVC. Moreover, the γ‐Fe₂O₃ particles were covered by FPVC in the γ‐Fe₂O₃/SPU/FPVC composite. The adsorption layer of FPVC protected SPU from catalytic degradation by γ‐Fe₂O₃, resulting in increasing hydrolytic stability for SPU. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 3030–3035, 2001     

Effect of surface modification of Fe<Subscript>3</Subscript>O<Subscript>4</Subscript> nanoparticles on the preparation of Fe<Subscript>3</Subscript>O<Subscript>4</Subscript>/polystyrene composite particles via miniemulsion polymerization

Fe₃O₄ nanoparticles were modified by n-octadecyltrimethoxysilane (C18TMS) and 3-trimethoxysilylpropylmethacrylate (MPS). The modified Fe₃O₄ nanoparticles were used to prepare Fe₃O₄/polystyrene composite particles by miniemulsion polymerization. The effect of surface modification of Fe₃O₄ on the preparation of Fe₃O₄/polystyrene composite particles was investigated by transmission electron microscopy, Fourier transform infrared spectrophotometer (FT-IR), contact angle, and vibrating sample magnetometer (VSM). It was found that C18TMS modified Fe₃O₄ nanoparticles with high hydrophobic property lead to the negative effect on the preparation of the Fe₃O₄/polystyrene composite particles. The obtained composite particles exhibited asymmetric phase-separated structure and wide size distribution. Furthermore, un-encapsulated Fe₃O₄ were found in composite particles solution. MPS modified Fe₃O₄ nanoparticles showed poor hydrophobic properties and resulted in the obtained Fe₃O₄/polystyrene composite particles with regular morphology and narrow size distribution because the ended C=C of MPS on the surface of Fe₃O₄ nanoparticles could copolymerize with styrene which weakened the phase separation distinctly.     

Anthranilic acid assisted preparation of Fe3O4–poly(aniline‐co‐o‐anthranilic acid) nanoparticles

Magnetic Fe₃O₄–poly(aniline‐co‐o‐anthranilic acid) nanoparticles were prepared by a novel and simple method: anthranilic acid assisted polymerization. The synthetic strategy involved two steps. First, Fe₃O₄ nanoparticles capped by anthranilic acid were obtained by a chemical precipitation method, and then the aniline and oxidant were added to the modified Fe₃O₄ nanoparticles to prepare well‐dispersed Fe₃O₄–poly(aniline‐co‐o‐anthranilic acid) nanoparticles. Fe₃O₄–poly(aniline‐co‐o‐anthranilic acid) nanoparticles exhibited a superparamagnetic behavior (i.e., no hysteresis loop) and high‐saturated magnetization (M_s = 21.5 emu/g). The structure of the composite was characterized by Fourier‐transform infrared spectra, X‐ray powder diffraction patterns, and transmission electron microscopy, which proved that the Fe₃O₄–poly(aniline‐co‐o‐anthranilic acid) nanoparticles were about 20 nm. Moreover, the thermal properties of the composite were evaluated by thermogravimetric analysis, and it showed excellent thermal stability. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 1666–1671, 2006     

Synthesis of Fe3O4@SiO2@MPS@P4VP nanoparticles for nitrate removal from aqueous solutions

In this study, synthesis of Fe₃O₄@SiO₂@MPS@poly(4‐vinylpyridine) core‐shell‐shell structure was investigated as an efficient adsorbent for removal of nitrate ions from aqueous solutions. Fe₃O₄ nanoparticles were initially prepared by co‐precipitation method, then the surface of Fe₃O₄ was coated with SiO₂ through a modified St öber method. Finally, the Fe₃O₄@SiO₂ nanoparticles were modified by 3‐(trimethoxysilyl) propyl methacrylate followed by emulsion polymerization of 4‐vinylpyridine. The resultant material was acidified in HCl solution to be effective for nitrate removal. The synthesized sample was characterized by X‐ray diffraction, transmission electron microscopy, field‐emission scanning electron microscopy, Fourier‐transform infrared spectra, thermogravimetric analysis (TGA), and vibrating sample magnetometer. The removal efficiency was optimized for some experimental parameters such as pH, contact time, and amount of sorbent loading. The maximum predictable adsorption capacity was 80.6 (mg nitrate/g sorbent) at optimum conditions. Also, regeneration of the nitrate adsorbed particles was possible with NaOH solution. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 44330.     

Magnetoelectric coupling in CoFe2O4-Pb(Zr0.2Ti0.8)O3 coaxial nanofibers

In this work, we reported the fabrication and magnetoelectric coupling properties of the multiferroic CoFe₂O₄-PbZr_0.2Ti_0.8O₃ (CFO-PZT) coaxial nanofibers synthesized by electrospinning technique. The coaxial structure of nanofibers was demonstrated by magnetic force microscope and transmission electron microscope. The multiferroic properties of coaxial nanofibers have been revealed by magnetic hysteresis loops and piezoresponse amplitude butterfly curves and phase hysteresis loops. The as-prepared coaxial nanofibers show an effective piezoelectric coefficient d₃₃ of 30 pm/V and a saturated magnetization of 12 emu/g. Their magnetoelectric response has been probed by means of the localized changes in magnetization after poling the domains of the composite system. A static, large converse magnetoelectric coupling coefficient of 1.2 × 10⁻⁸ s/m was obtained in a single CFO-PZT nanofiber.     

Preparation of novel hydrophobic magnetic Fe3O4/waterborne polyurethane nanocomposites

Magnetic Fe₃O₄/waterborne polyurethane nanocomposites were synthesized based on waterborne polyurethane (WPU) and amino-functionalized Fe₃O₄ by in situ polymerization. The Fe₃O₄ nanoparticle was found to be uniformly distributed in Fe₃O₄/WPU nanocomposites with linear or crosslinked structure. In addition, the formation mechanism and magnetic conduction mechanism of stable inorganic–organic nanocomposites were discussed. The experimental results showed that the thermal stability, magnetic, and mechanical properties of magnetic Fe₃O₄/waterborne polyurethane nanocomposites were improved by amino functionalized Fe₃O₄. Furthermore, the defoaming property of the emulsion and the hydrophobic property of magnetic Fe₃O₄/waterborne polyurethane nanocomposites were improved by the 1-hexadecanol-terminated prepolymer. What more, polycaprolactone (PCL)-based Fe₃O₄/WPU nanocomposites have excellent mechanical properties (The tensile strength is over 30 MPa, the elongation rate is above 300%.) and magnetic properties. Magnetic Fe₃O₄/waterborne polyurethane nanocomposites will be used in the field of hydrophobic and microwave absorbent materials. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020 , 137, 48546.     

Energy transfer to Eu(III) in the solid‐state low‐density polyethylene–poly(acrylic acid) and low‐density polyethylene–Fe2O3–poly(acrylic acid) matrices

Ion exchange between H⁺ and Eu³⁺ and/or Tb³⁺ was studied in the material modified by in situ sorption and thermal polymerization of acrylic acid in low‐density polyethylene (LDPE–PAA) and in the composite system LDPE–Fe₂O₃–PAA. Fluorescence spectroscopy showed evidence of Eu³⁺ and/or Tb³⁺ ion exchanges in these materials. The matrix LDPE–PAA after Eu(III) ion exchange presented luminescence (excitation 265 nm). This was explained by an energy‐transfer process from the matrix LDPE–PAA to Eu³⁺ ions. The LDPE–PAA matrix after simultaneous Eu³⁺/Tb³⁺ ion exchange exhibited Eu³⁺ and Tb³⁺ ion luminescence (excitation 265 nm), confirming an energy‐transfer process from LDPE–PAA to Eu³⁺ ions in LDPE–PAA–Eu³⁺–Tb³⁺ matrix. Fe₂O₃ in LDPE–Fe₂O₃–PAA quenched the matrix for excitation at 265 nm and no emission at the region 400 nm was observed. The luminescence of Tb³⁺ ions in the matrix LDPE–Fe₂O₃–PAA–Tb³⁺ (excitation 265 nm) was partially quenched by Fe₂O₃. However, a weak emission of Eu³⁺ ions was observed (excitation 265 nm) in the matrix LDPE–Fe₂O₃–PAA after simultaneous Eu³⁺ and Tb³⁺ ion exchanges, suggesting an energy transfer from Tb³⁺ to Eu³⁺ ions. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 78: 919–931, 2000     

Size and Lone Pair Effects on the Multiferroic Properties of Bi0.75A0.25FeO3−δ (A = Sr,Pb, and Ba) Ceramics

The work presents a comparative study of the effects of divalent Ba, Sr, and Pb substituents on the multiferroic properties of BiFeO₃. The multiferroic properties of Bi_0.75A_0.25FeO₃ (A = Sr, Pb, Ba) solid solution have been explained taking into account the effects of size differences and electronic configuration differences between the host element (Bi) and the substituent. X‐ray diffraction studies revealed that Sr and Pb substitution at Bi‐site transforms the rhombohedral phase (R3c) to cubic phase (Pm3m), whereas the Ba‐substituted sample exhibited the presence of both rhombohedral and cubic phases (R3c + Pm3m). Electronic structure studies through XPS revealed that charge imbalance induced by divalent substitution was being compensated by the formation of oxygen vacancies, while the Fe ions exist in Fe²⁺ and Fe³⁺ states. Replacement of volatile Bi by Sr, Pb, and Ba reduces the concentration of oxygen vacancies (V_O²⁺) and helps to improve the dielectric properties. Strong magnetization enhancement was observed in the substituted compositions and was seen to be consistent with the suppression of cycloid spin structure due to structural transformation as well as possible changes in Fe–O local environment leading to local lattice distortion effects. Furthermore, the observed decrease in the values of magnetic coercivity at low temperature in all the substituted samples is explained in terms of reduced effective single ion anisotropy, originating in the magnetoelectric coupling and being a particularly stronger effect in the case of the lone pair dopant Pb, consistent with theoretical predictions. The lone pair substituent Pb leads to the largest dielectric constant, enhanced magnetization, and large effects on the low‐temperature hysteresis.