Zinc Substitution Research Articles

Machine Learning-Based Prediction of Cyclic Voltammetry Behavior of Substitution of Zinc and Cobalt in BiFeO3/Bi25FeO40 for Supercapacitor Applications.

Artificial intelligence and machine learning have become indispensable tools across various disciplines in the present century. In that way, the role of artificial intelligence and machine learning in energy storage devices was investigated. As a preliminary study, the data derived from electrochemical studies were used for the prediction. The prediction of current from cyclic voltammetry (CV) studies was undertaken for bismuth ferrite (BFO), substitution of zinc in BFO (BFZO), and substitution of cobalt in BFO composite (BFCO). CV is a vital electrochemical technique used for studying the electrochemical behavior of any material. The electrochemical study provides insights into the energy storage behavior of the material through the specific capacitance. The machine learning models, such as Artificial Neural Network (ANN), Random Forest (RF), and XGBoost (XGB), are trained and implemented to predict current at different scan rates. These models are trained and validated using the data collected from a CHI 600E electrochemical workstation. Multiple trials of experiments were performed to build the most optimum model for the material. The predicted values provide promising results and align well with the experimental data. The XGBoost, ANN and RF models perform well for the CV data set with an average testing accuracy >97%. Also, a meta-model was created using stacking of the above three machine learning models which further improved the predictive performance, achieving a slightly higher average testing accuracy of over 97.73%. The outcomes from the models can promote the development of machine learning applications in the field of electrochemistry and provide insights into optimizing supercapacitor performance and design through data-driven approaches.

Effect of zinc substitution on structural, electrical, dielectric and magnetic properties of magnesium nano-ferrites prepared by co-precipitation route

Zinc substituted Magnesium ferrites synthesized by using Co-precipitation method. The structural characterisations of samples are carried out and formation of single-phase nickel ferrite was substantiated through powder X-ray diffraction. The lattice parameters were calculated that are in the range 8.323–8.361 Å.Surface morphology of samples were also investigated through Scanning electron microscopic (SEM) analysis. SEM images revealed clear grain structures of synthesised samples. Magnetic measurements showed the ferromagnetic behaviour, analysed through vibrating sample magnetometer (VSM) while magnetic parameters obtained using VSM measurementat room temperature. MS and HC were found to decrease with increases in the Zn concentration due to non-magnetic behaviour of zinc. The dielectric dispersion for the Mg–Zn ferrites were determined as a function of frequency (50 Hz to 5 MHz). The dielectric constant and the loss tangent decrease expeditiously with incrementing frequency, and then reaches a constant value. The semiconducting behaviour of Mg-Zn ferrites proved by measuring resistivity as a function of temperature and materials are showing thermistor relatively good thermistor constants, they can be utilized as thermistors. The results were discussed in detail in this research article.

Substituted hydroxyapatite and β-tricalcium phosphate as osteogenesis enhancers

Hydroxyapatite and β-tricalcium phosphate are the most popular calcium phosphates used for bone tissue regeneration and in the manufacture of prostheses for bone replacement. Incorporation of different ions in low concentrations into the crystal lattice of calcium phosphates allows enhancing or modifying their properties. In this work, stoichiometric hydroxyapatite, calcium deficient hydroxyapatite and β-tricalcium phosphate co-substituted with zinc, magnesium, and silicate were synthesized using a mechanochemical approach. The compositions of the materials were investigated by powder X-ray diffraction, FTIR spectroscopy and scanning electron microscopy. The materials prepared were assessed for dissolution in water and implanted into rat skull bones. For the first time, it was demonstrated that the substituted calcium-deficient hydroxyapatite has an increased solubility in water compared with β-tricalcium phosphate and hydroxyapatite. In vivo studies revealed that the calcium-deficient hydroxyapatite promotes better osteogenesis than other calcium phosphates investigated here, showing almost complete remodeling of the damaged bone tissue already after 5 months. In this regard, calcium-deficient hydroxyapatite with zinc, magnesium, and silicate substitution is the most promising material for bone tissue regeneration.

The effect of zinc substitution on the optical properties of Sm3+ doped zinc borate glasses

Zinc borate glasses are a relatively well known glass type that can be produced at comparably low temperatures. Variations in both the type and concentration of network modifier atoms induce structural alterations within the glass matrix. If doped with optically active dopants, e.g. rare earth ions, compositional changes also affect the local surrounding of the dopants and consequently their optical properties such as emission peak shape and peak ratio. To investigate the effect of different low field strength network modifier ions in zinc borate glasses two glass series were prepared using the melt quench technique; Sm3+ was used as dopant ion: 50B2O3, xK2O, (49-x)ZnO, 1Sm2O3 (x = 5,10,15, …, 30 mol%) and 50B2O3, 30MO, 19ZnO, 1Sm2O3 (M = Ca, Sr and Ba). It is found that the substitution of ZnO for K2O notably enhances the intensity of the red Sm3+emission. Based on the literature this effect is attributed to a change in symmetry at the rare earth position. Additionally, the effect of network modifier concentrations and the different network modifier types on the Sm3+ absorption spectra is examined, discussed and compared to literature data. Furthermore, the glasses are characterized according to their density, refractive index, molar volume, and oxygen packing density.

Mn- or Zn-substituted goethite enhancing tetracycline degradation by increasing oxygen vacancies and promoting electron transfer

The metal-substituted goethite with addition of oxidants can effectively promote the degradation of antibiotics, but the usage of external agents restricts its application in in-situ remediation of antibiotic pollution. In this study, the metal-substituted goethites were prepared through co-precipitation method to investigate the effects of using manganese (Mn) or zinc (Zn) substitution alone on tetracycline (TC) degradation, combining with microscopic characterization and electrochemical methods. The results showed that the degradation rate constants of the first stage on Mn or Zn-substituted goethite were 0.299 h-1 and 0.498 h-1, respectively, which were about 2 and 4 times of the pristine goethite (0.117 h-1). In the pH range of 4.0–9.0, Mn or Zn substitution significantly promoted TC degradation. Free and non-free radical pathways existed in the process of TC degradation by Mn or Zn-substituted goethite. The active site change and enhanced electron transfer ability were the main reasons for promoting degradation. Mn or Zn substitution increased oxygen vacancy (OV) content and promoted the electron transfer between TC and goethite. In Zn-substituted goethite, the coupling of OV and electron transfer produced free radicals, and in Mn-substituted goethite, the redox reaction induced mainly by electron transfer produces free radicals. This study reveals a new mechanism of efficient degradation of TC by iron minerals without the need for external oxidants, and the materials studied can be used for in-situ remediation of antibiotic contaminated groundwater.

A review of recent advances of kesterite thin films based on magnesium, iron and nickel for photovoltaic application: insights into synthesis, characterization and optoelectronic properties

Abstract This review emphasizes the recent advancements and prospects of thin-film kesterite-based photovoltaic (PV) applications using magnesium, iron and nickel. The quest for novel materials employed in solar cells has resulted in incorporating these elements into the composition of kesterite as substitutes or modifiers (dopants) for zinc. This integration has induced notable repercussions on the structural, optoelectronics and morphological properties, which are reviewed. The first section of this paper offers a comprehensive review of the general characteristics of kesterite minerals. These crucial materials exhibit a high absorption coefficient (104 cm–1) and an optical band gap of 1.0–1.8 eV. Moreover, they are free of critical raw materials, non-toxic and sustainable. The second section depicts the substitution or modification of zinc by magnesium in kesterite. Additionally, this paper provides a comprehensive review of the quaternary and pentanary systems Cu2MgSn(S,Se)4 and Cu2Zn1–xMgxSnS4, highlighting their advantages and drawbacks. In the last section, a review of the quaternary or pentanary systems is conducted, namely Cu2ZnxFe1–xSnS4 and Cu2ZnxNi1–xSnS4, along with their effects on optoelectronic properties. In conclusion, various methods for obtaining modified or substituted kesterite materials using magnesium, iron and nickel have demonstrated sustainability, scalability for industrial production and potential candidacy as substitutes for conventional PV materials. The prospects for pentanary materials (Cu2Zn1‑xMgxSnS4, Cu2Zn1‑xFexSnS4 and Cu2Zn1‑xNixSnS4) are to overcome the efficiency record of kesterite reported in 2014, which was 12.6 % for Cu2ZnSn(S,Se)4, and to enhance its optoelectronic properties through synthesis conditions that comply with the principles of green chemistry.

Exploring the effect of zinc substitution in nanocrystalline nickel ferrite for enhanced supercapacitor and gas sensing applications

A hydrothermal method was employed to synthesize Zn-substituted nickel ferrite nanoparticles at an optimized reaction temperature of 175 °C. X-ray diffraction analysis of as-synthesized nanoparticles exhibited a cubic spinel structure, and the average crystallite size decreased from 41 nm to 31 nm with increasing dopant concentration. Morphological study confirmed the cubic shape of the prepared nanoparticles. Raman spectra exhibited five Raman active modes (A1g + Eg + 3T2g), which are attributed to ferrite. The dielectric constant decreased and became constant with increasing frequency, whereas the AC conductivity demonstrated an increasing trend. The oxidation state and elemental composition of Zn2+, Ni2+ and Fe3+ in Zn-doped NiFe2O4 were confirmed by XPS measurements. Mossbauer spectra were recorded to determine the oxidation state of the iron. The coercivity increased with increasing Zn concentration. The Day plot analysis confirmed the pseudo-single-domain nature of the as-synthesized nanoparticles. Pseudocapacitive behavior was observed for all samples, whereas a high Csp value was achieved for ZNF3 (598 F/g). The LPG sensor made out of the synthesized nanoparticles demonstrated faster response and recovery times of 13 and 31 s, respectively, when exposed to a concentration of 10 ppm.

Tuning the Magnetic Behavior of Zinc Ferrite via Cobalt Substitution: A Structural Analysis.

Cobalt-doped zinc ferrite is a contemporary material with significant structural and magnetic characteristics. Our study explores the magnetic properties of cobalt-substituted zinc ferrite (ZnxCo1-xFe2O4), synthesized via a simple sol-gel method. By varying the cobalt ratio from 0 to 0.5, we found that zinc substitution impacts both the magnetization and lattice parameters. FTIR analysis suggested the presence of functional groups, particularly depicting an M-O stretching band, within octahedral and tetrahedral clusters. X-ray diffraction analysis confirmed the phase purity and cubic structure. The synthesized materials exhibited an average particle size of 24-75 nm. Scanning electron microscopy revealed the morphological properties, confirming the formation of truncated octahedral particles. In order to determine the stability, mass loss (%), and thermal behavior, a thermal analysis (thermogravimetric analysis (TGA)/differential thermal analysis (DTA)) was performed. The magnetic properties of the synthesized ferrites were confirmed via a vibrating sample magnetometer (VSM). Finally, the highest saturated magnetization and lowest coercivity values were observed with higher concentrations of the cobalt dopant substituting zinc. The synthesized nanomaterials have good stability as compared to other such materials and can be used for magnetization in the near future.

Structural, optical, electrical and magnetic properties of lithium zinc ferrite – Silica nanocomposites

Lithium zinc ferrite - silica nanocomposites; with a formula [Li0.5−x/2ZnxFe2.5−x/2O4]30%[SiO2]70%, have been synthesized using ultrasonic assisted sol-gel auto combustion method. Thrust of the study is to investigate effect of zinc substitution in lithium ferrite (dispersed in silica matrix) on structural, optical, electrical and magnetic properties. X-ray diffraction (XRD), UV Visible (UV-Vis), Transmission Electron Microscopy (TEM), Complex Impedance Spectroscopy (CIS) and Vibrating Sample Magnetometry (VSM) have been employed to investigate the samples. XRD patterns confirm the phase purity and revealed that incorporation of Zn2+ at Li+ sites expand the unit cell dimensions from 8.3281 Å to 8.4398 Å, strain and crystallite size escalates from 0.29 to 1.42 and 18.28–27.50 nm respectively. Results from TEM and XRD match well indicating least agglomeration. Optical bandgap and refractive index show a significant effect on increasing zinc content. The impedance (Z) is found to reduce with increase in Zn2+ and may be attributed to enhancement in crystal boundaries. Dielectric properties were explored using cole-cole theoretical fitting of permittivity (ε), universal dielectric response (UDR) model, Koop’s theory and Maxwell–Wagner (M-W) mechanism. Complex electrical modulus (M*) formulation has been employed to explore the transport mechanism. Cole-cole plots in M* reveal that all the samples, except x = 0.50, show relaxation originating from grain boundaries whereas x = 0.50 sample shows contributions from both, grain and grain boundaries. Equivalent circuits have been derived using M* spectrum and are presented with circuit parameters. Frequency dependent AC conductivity (σac) curves have been fitted successfully using Jonscher’s power law; σac for a typical sample x = 0.50 was fitted using double power law. All samples have η ≤ 1, confirming correlated barrier hopping (CBH) mechanism of conductivity. Present system exhibits lower dc conductivity due to highly resistive silica in the samples. Magnetic properties have been studied using Vibrating Sample Magnetometry (VSM). Zn2+ substitution has a significant impact on magnetization due to migration of cations.

Enhanced magnetic hyperthermia efficiency in poly vinyl alcohol-coated zinc-substituted cobalt ferrite nanoparticles: Correlated effects of zinc content and applied magnetic field strength

Finding the interrelation among the magnetic response of the heat mediators to an alternating magnetic field (AMF) and other relevant parameters in magnetic hyperthermia therapy (MHT) can give the possibility to accurately design high-performance nanostructured magnetic nanoparticles (MNPs). In this context, the present work investigates the effect of the zinc substitution on magnetic properties and heat-generating ability of poly vinyl alcohol-coated Zn-substituted cobalt ferrite nanoparticles (PZC NPs) with different zinc contents (ZnxCo1−xFe2O4; x = 0, 0.15, 0.3, 0.4, 0.5, 0.7), synthesized using hydrothermal-assisted co-precipitation method. The obtained results showed that the PZC NPs with an average particle size ∼ 15 nm exhibit ferrimagnetic features and their coercivity (Hc) values decrease as the zinc content (x) increases. Moreover, as Zn2+ replaces Co2+ in the structure, saturation magnetization (Ms) increases up to about 52 emu/g for PZC-30 NPs (x =0.3) and then decreases for higher Zn contents. The hyperthermia measurements were performed at a fixed filed frequency (f=120kHz) and different magnetic field strengths (Happl=17,20,24.5kA/m). The results revealed that, as x increases, specific absorption rate (SAR) at each Happl first shows an increasing trend and then reaching a maximum value (at x=0.4) follows a decreasing trend. Moreover, the highest SAR (25.25 W/g) belongs to the magnetic fluid containing PZC-40 NPs at Happl=24.5kA/m. Furthermore, the Happl-dependency of the SAR values were obtained as a power law (SAR∼Happln) in which the exponent n rises as x decreases, suggesting that the optimal composition tends to shift to ones with the lower x at higher Happl. The obtained results, revealing the high impact of the interrelation between the chemical composition and the Happl on the MNPs heating efficiency, can shed more light on the way to design heat mediators with optimal performance through simultaneous control of the chemical composition and the Happl.

The nature of the frequency dependence of the adiabatic temperature change in Ni50Mn28Ga22-x(Cu, Zn)x Heusler alloys in cyclic magnetic fields

This study presents the results of direct measurements of the adiabatic temperature change (∆Tad) in Ni50Mn28Ga22−x(Cu, Zn)x (x = 0; 1,5) alloys in cyclic magnetic fields of 0.62 and 1.2 T at frequencies f= 1, 5, 10, and 20 Hz. The substitution of zinc and copper for the initial composition resulted in a decrease in ∆Tad and a stronger frequency dependence. The strong frequency dependence of ∆Tad near TC in the Ni50Mn28Ga22−x(Cu, Zn)x system is due to the inhomogeneous microstructure and the coexistence of martensite-austenite phases, which give rise to two simultaneously acting mechanisms. Firstly, the addition of Zn and Cu increases the coercive force HC, resulting in an increase in the viscosity coefficient. Secondly, an increase in the frequency of the cyclic magnetic field (i.e., an increase in the field sweep rate) leads to the same effect, increasing the viscosity coefficient. Which, in our opinion, is the reason for the frequency dependences of ∆Tad near TC. The study found that the specific cooling power (SCP) for the Ni50Mn28Ga22 sample in a cyclic magnetic field of 1.2 T increased with frequency, reaching 4.75 W/g at 20 Hz, which is 14.1 times greater than at 1 Hz. This suggests that, under conditions of sufficient heat exchange, the cooling efficiency of a magnetic refrigerator can be greatly improved by increasing the operating frequency.

Structural regulation of Mn-based Prussian blue induced by zinc-substitution for enhanced sodium storage performance

Mn-based Prussian blue (NMF) is a prospective choice for sodium-ion battery cathode materials because of its high theoretical specific capacity, high charge/discharge voltage plateau, cheap raw materials and eco-friendly. However, it undergoes serious capacity fading during cycling owing to the unstable Jahn-Teller distortion caused by the oxidation of Mn2+ to Mn3+. In this work, the structural regulation of NMF is achieved through zinc substitution, and the effect of structural adjustment caused by zinc substitution on the sodium storage properties of NMF is studied in detail. The experimental results verify that NZMF still maintain cubic structure with high content of sodium, less [Fe(CN)6] vacancies and low level of crystal water. Moreover, the four coordination of Zn-N is lower than six coordination of Mn-N, confining the nucleus growth, thereby reducing the powders size of NZMF. The smaller powder size of NZMF with higher surface area results in shortened sodium ion diffusion path and accelerated the charge transfer. In addition, the electrochemically inactive zinc plays a pillar role in maintaining its structural stability. Consequently, NZMF reveals better rate capacity and cycling stability than original NMF. In particular, its capacity can be maintained at 68.6 mAh g−1 under a high current density of 1600 mA/g, and the capacity retention is 76.5% at 800 mA/g after 1000 cycles. This work provides a new insight to improve the structural stability of Prussian blue.

The effects of Zn doping on the thermoelectric performance of Cu12Sb4S13

In this study, first-principles electronic structure calculations and Boltzmann transport theories were used to understand the thermoelectric behavior of tetrahedrites. Calculations were performed on zinc (Zn)-substituted derivatives with zinc occupying each lattice site in the parent compound Cu12Sb4S13 to study the zinc substitution mechanism and the relation between the zinc substitution site and thermoelectric performance. It was found that the most energetically favorable sites for zinc are the Cu(1) sites, and the next are the Cu(2) sites. Furthermore, the room-temperature Seebeck coefficient of the host was enhanced nearly 255 and seven times by zinc doping at Cu(1) and Cu(2) sites, respectively, owing to the decrease in carrier concentration and the increase in band effective mass, respectively. However, the electrical conductivity showed a marked decrease upon zinc doping at Cu(1) and Cu(2) sites, due to the decrease in carrier contribution and low mobility, respectively. As a result, Cu12Sb4S13 compounds substituted with zinc at Cu(1) sites have a preferable optimizing power factor at room temperature. The optimizing power factor of the host could obtain approximately eight times improvement at room temperature upon zinc substitution at Cu(1) sites.

Electron spin resonance and induction heating studies of zinc substituted (Mn, Co) ferrite nanoparticles for potential magnetic hyperthermia applications

This study presents an investigation on the various spin relaxation processes taking place at X-Band microwave energy in Zn substituted MnFe2O4 and CoFe2O4 and their induction heating studies. The material properties of these citric acid assisted sol-gel synthesized nanoparticles have been explored using X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), Field emission scanning electron microscope, Vibrating sample magnetometer (VSM) and Electron spin resonance spectroscopy. XRD and Rietveld refinement confirm the face centered cubic spinel structure of the synthesized samples, which is further supported by the observation of absorption bands characteristic of the spinel ferrites in the FTIR spectra. The remanence, coercivity and effective magnetocrystalline anisotropy values from VSM studies show lower value with zinc substitution which is desirable for biomedical application. Various spin resonance parameters like gyromagnetic ratio, peak to peak linewidth, resonance field, spin-lattice and spin-spin relaxation times have been calculated. The induction heating studies of the samples in an alternating magnetic field have been carried out using a field strength of 4.58 × 109 Am-1s-1. All the investigated MNPs are able to raise the temperature to the therapeutic limit of 42–45 °C. The specific absorption rate (SAR) which describe the heating potential of the MNPs is calculated using four different concentrations of each sample - 5 mg mL-1, 10 mg mL-1, 15 mg mL-1 and 20 mg mL-1. SAR values are found to decrease with increase in concentration and achieve the highest value of 303 W/g for Co0.5Zn0.5Fe2O4 nanoparticles with 5 mg mL-1 concentration. The ability of the MNPs to give rise to the therapeutic temperature points toward their suitability as an effective heat mediator in magnetic hyperthermia treatment of cancer.

Micro-structural and magnetic analysis of spinel high entropy oxides synthesized by two-step pressureless sintering provides insight into high entropy ceramics

High-entropy oxides are novel materials consisting of many metallic elements of equal proportions. Hence, the complex structure of high-entropy oxides leads to interesting properties. In this work, seven single-phase high entropy oxides were synthesized by two-step pressureless sintering. According to the experimental XRD data, all samples are found in the cubic crystal structure with the Fd-3m space group. This result shows that high entropy oxides have a high possibility of phase formation. For all samples, the EDS results show that all expected elements have similar elements content. The magnetization curves show that the magnetic properties change systematically with the changes in the high-entropy stable oxide composition. The seven different samples are divided into three groups for comparison. In group 1, with the substitution of iron for zinc, Hc increased from 19 Oe to 221 Oe, while Ms changed slightly. In group 2, the substitution of zinc for nickel leads to the rapid weakening of magnetism. In group 3, with nickel replacing cobalt, Ms increased from 15.060 emu/g to 19.801 emu/g, and Hc decreased from 28 Oe to 11 Oe. The complex element composition makes high entropy materials have great development space in the field of magnetic materials. Thus, the magnetic properties of the high-entropy spinel oxides can be adjusted according to this concept.

Effects of Zinc Substitution on the Microstructural and Magnetic Characteristics of Cubic Symmetry Nickel Ferrite System

The preparation of ZnxNi1−xFe2O4 (x = 0 and 0.3) nanoparticles using glycine-mediated combustion route was successfully completed depending on the zwitterion and combustion characteristics of glycine. Using a variety of methods, including XRD, FTIR, SEM/EDX, and TEM, the investigated ferrites were characterized. XRD and FTIR analyses confirm that Zn0.3Ni0.7Fe2O4 and NiFe2O4 nanoparticles crystallize in the cubic symmetry in the space group Fd3m. An increase in the lattice parameters and a subsequent decrease in crystallite size were caused by the process of replacing Ni ions with Zn ions. In accordance with Waldron’s hypothesis, FTIR spectra demonstrate that the ferrites have a spinel-type structure as they are produced. The substitution process by Zn led to different changes in the half band widths with subsequent in splitting in the absorption band around 400 cm−1. The examined ferrites’ cation distribution showed that Zn2+ and Ni2+ ions favored the tetrahedral (A) and octahedral (B) sites, respectively, while Fe3+ ions occupied both A- and B-sites, providing mixed spinel ferrite. TEM analysis indicates the formation of spinel nanocrystalline particles with low agglomerations. The particle size of the as-synthesized ferrites did not exceed 16 nm. By applying the VSM approach at room temperature, the magnetic characteristics of the ferrites under investigation were established. The magnetization of Zn0.3Ni0.7Fe2O4 nanoparticles was found to be higher than that of NiFe2O4 nanoparticles according to the magnetic data. Increasing the magnetization and the experimental magnetic moment of Zn0.3Ni0.7Fe2O4 were accompanied by a decreasing of its coercivity. The net magnetization is oriented along different high symmetry directions. On the other hand, the anisotropy of the nickel ferrite increases by substituting Ni with a Zn ion.

Microstructure and magnetization study of Li and Li–Zn ferrites synthesized by an electron beam

Lithium ferrites are widely used in high frequency electronic devices. The present work reports structural and magnetization analysis of lithium (Li0.5Fe2.5O4) and lithium-zinc (Li0.4Fe2.4Zn0.2O4) ferrites synthesized by electron beam heating (RT) of powdered and compacted samples. The synthesis was carried out at 600 and 750 °C for up to 120 min using 2.4 MeV electron beam generated by an ILU-6 pulsed electron accelerator. The characteristics of the samples synthesized by RT were compared with the ones of samples obtained by traditional thermal heating under the same temperature and time conditions. From XRD and thermomagnetometric analyses, α-Li0.5Fe2.5O4 ordered spinel phase and Li0.5(1−x)Fe2.5−0.5xZnxO4 ferrite phase with different zinc substitution were formed from Fe2O3/Li2CO3 and Fe2O3/Li2CO3/ZnO reagents, respectively. RT synthesis significantly increases the rate of interaction between the initial powders and, as a consequence, the rate of ferrite phase formation. In this case, lithium-containing ferrites can be successfully achieved from compacted powders at 750 °C, which is lower than the temperature of synthesis in conventional thermal heating. The average crystallite sizes calculated from the XRD and BET analyses were 114 nm for Li, 120 nm for Li–Zn ferrites and 142 for Li, 150 nm for Li–Zn, respectively. The specific saturation magnetization and Curie temperature were estimated and are 60 emu/g for Li, 70 emu/g for Li–Zn ferrites and 632 °C for Li, 492 °C for Li–Zn ferrites, respectively. The data obtained in this work are of considerable interest for the creation of a technology for producing ferrites at low synthesis temperatures.

Effect of zinc substitution for manganese on microstructural, optical and photocatalytic properties of LaMnO3 nanoparticles

Effect of zinc substitution for manganese on microstructural, optical and photocatalytic properties of LaMnO3 nanoparticles

Emergence of Dielectric Properties by Doping of Semi‐Transition Metal in Semiconductor Complex Perovskite Oxide

AbstractThe effect of zinc substitution at the Cu2+ site and germanium substitution at the Ti4+ site in bismuth copper titanate, Bi2/3Cu3Ti4O12, is investigated. Composition with x = 0.05 is synthesized by semi‐wet route in the system Bi2/3Cu3Ti4−xGexO12 (BCTGO) and Bi2/3Cu3−xZnxTi4−xGexO12 (BCZTGO) that are sintered at 1123 K for 8 h. Crystal structure has remained cubic. The phase formations of these ceramics are confirmed by the X‐ray diffraction. The microstructural analysis of the samples is done by scanning electron microscopy and tunneling electron microscopy. Elemental analysis is performed by energy dispersive X‐ray spectroscopy. X‐ray photoelectron spectroscopy suggests that all elements present in these ceramics are in proper oxidation states. The dielectric constant is found high for BCTGO‐0.05 ceramic. The specific capacitances of BCTGO‐0.05 and BCZTGO‐0.05 are found to be 13.05 and 15.7 F g−1, respectively. Optical band gap values (Eg) of BCTGO‐0.05 and BCZTGO‐0.05 ceramics are found as 1.77 and 1.91 eV.

Effect of the zinc substitution on the physical and optical properties of tellurium vanadate glasses

In this communication, we report the physical and optical properties of xZnO-(60-x)TeO2-40V2O5 (x = 20, 25, 30, 35, and 40 mol%) glass systems. The glasses were prepared using the melt-quenching method. The amorphous nature of the glass systems was confirmed using powder X-ray diffraction. We have elucidated the changes in the rigidity and elastic moduli of the glass system as a function of composition. These changes were measured in terms of changes in the physical parameters like density, molar volume, and packing density of the glasses. The elastic moduli of the glass systems, like Young's modulus, bulk modulus, shear modulus, longitudinal modulus, and Poisson's ratio, were estimated using Makishima-Mackenzie's theory. The changes in the elasticity of the present system were correlated with the structural changes occurring in the glasses by adding ZnO at the expense of TeO2. The optical properties of the glass system were found by means of diffuse reflectance spectroscopy. Using Kubelka Munk method, the corresponding band gap energy and Urbach energy of the glass system were estimated. The present investigation sheds light on understanding the concentration effect of ZnO in the glass network.