Cobalt Zinc Ferrite Nanoparticles Research Articles

Probing temperature-dependent magnetism in cobalt and zinc ferrites: A study through bulk and atomic-level magnetic measurements for spintronics

Spinel ferrites (MFe2O4) are integral to various industries, particularly spintronics, which utilizes the intrinsic spin of electrons as well as the electronic charge to develop devices that dictate spin-based transport, advancing new memory, logic applications, and improving magnetic storage technologies. These materials are valued for their exceptional optical, magnetic and electrical properties, and their easily tunable shape and size. This flexibility of spinel ferrites and their connection to the material’s magnetic behavior can be investigated by studying a range of spinel ferrite structures. In this study, the magnetic behaviors of cobalt ferrite (CFO) and zinc ferrite (ZFO) nanoparticles were examined using a vibrating sample magnetometer (VSM, bulk magnetometry) and X-ray Magnetic Circular Dichroism (XMCD, atomic magnetometry). The Rietveld refinement of XRD data supported single phase spinel structure, while X-ray Absorption Spectroscopy (XAS), particularly through the Co L-edge XANES analysis, detected both Co2+ and Co3+ ions in CFO, suggesting significant ferromagnetic behavior due to octahedral site occupation. In contrast, ZFO exhibited antiferromagnetic character, with Zn2+ ions in tetrahedral sites, and canted antiferromagnetism manifesting as a hysteresis loop below 300 K, potentially related to lattice distortions or strain. At the atomic scale, XMCD analysis, along with sum rules, estimated the average magnetic moments for cobalt and zinc ferrites to be 3.045 ± 0.1 (1.448 ± 0.1) and 0.657 ± 0.1 (2.12 ± 0.1) μB at temperatures of 300 K (90 K), respectively. However, VSM-based bulk measurements indicated magnetic moments of 2.566 (2.288) and 0.281 × 10−3 (0.6503 × 10−3) μB for CFO and ZFO, respectively, at the same temperatures. The observed variation between bulk and atomic-scale magnetic moments points to complex interstitial interactions within the spinel ferrite’s sublattices. This discrepancy between the atomic-scale and bulk magnetic moments suggests intricate interstitial interactions within the spinel ferrite’s sublattices. These insights into the structural and magnetic intricacies of spinel ferrite nanoparticles enhance our understanding, facilitating the design of cutting-edge spintronic devices.

Dielectric and electrocaloric properties of BCTZ composite with cobalt zinc ferrite nanoparticles

Dielectric and electrocaloric properties of a multiferroic composite constituted from Ba0.85Ca0.15Ti0.9Zr0.1O3 (BCTZ) and Co0.4Zn0.6Fe2O4 (CZF), chosen for their closely related transition temperatures, are reported. Dielectric characteristics of the composites in the 1 kHz−10 MHz angular frequency range are described by two Cole-Cole relaxation models (domain wall and charge carrier) whereas for frequency <1 kHz, it is explained by Maxwell-Wagner type interfacial polarization using Jonscher power law. The effect of CZF phase on the dipolar mechanisms as a function of CZF mole fraction and the temperature are discussed. The electrocaloric property of the composites is estimated indirectly by Maxwell thermodynamic relation.

Agaricus Bisporus Mediated Synthesis of Cobalt Ferrite, Copper Ferrite and Zinc Ferrite Nanoparticles for Hyperthermia Treatment and Drug Delivery

Agaricus Bisporus Mediated Synthesis of Cobalt Ferrite, Copper Ferrite and Zinc Ferrite Nanoparticles for Hyperthermia Treatment and Drug Delivery

Comparing the two concentrations of Co0.6 Zn0.4 Fe2O4 nanoparticles coated with dimercaptosuccinic acid based on T2-and T2*- weighted MRI: An animal study

PurposeThis study aimed to compare two different concentrations of Cobalt-zinc (Co–Zn) ferrite (Co0.6 Zn0.4 Fe2O4 or CZFO) nanoparticles (NPs) included 1.5 and 2.5 mg Fe/kg coated with dimercaptosuccinic acid (DMSA) based on T2-and T2*- weighted magnetic resonance imaging (MRI) of rats liver. Materials and methodsThe structural and crystal phase of CZFO magnetic NPs were determined using X-ray diffraction (XRD) and FTIR analysis. Two groups of rats (six for each group) were studied, in which the first and second groups received 1.5 and 2.5 mg/ml of Fe/kg body weight of the mentioned NPs, respectively. After the injection of the NPs, the signal intensity of the liver at different times (30, 38, 75, and 120 min) as well as the pathological characteristics of the liver and kidney tissues (24 h after injection) were investigated for the two groups. ResultsFor group 1, the maximum contrast enhancement in the rat liver was 58.46% and 77.13% occurred at 30 and 120 min, respectively, for T2 and for T2* weighted images. For group 2, these values were obtained at 57.96% and 75.77% occurred at 30 and 75 min, respectively. There was not found a remarkable iron in the kidney tissue, however, a small amount of iron was observed in the two rats livers for each investigated group, which was negligible after 24 h. ConclusionOur results demonstrated that for both investigated groups, it seems that the synthesized CZFO NPs coated with DMSA are appropriate agents for increasing the contrast intensity based on T2-and T2*- weighted MR imaging in rat liver.

Eco-friendly synthesis of cobalt-zinc ferrites using quince extract for adsorption and catalytic applications: An approach towards environmental remediation

Cobalt-zinc ferrite nanoparticles were synthesized using environmentally friendly approach with quince extract as a reducing agent. Crystal structure and morphology of the obtained materials were studied by XRD, SEM-EDS, Mössbauer and IR spectroscopy. The synthesized nanoparticles have a cubic spinel structure and crystallite size ranging from 5 to 9 nm. The infrared spectra contain characteristic absorption bands for the MA-O (∼560 cm−1) and MB-O bonds (∼420 cm−1). Force constants were calculated for both tetrahedral and octahedral bonds. As the Co content increases, the force constant for the tetrahedral bond increases and the force constant for the octahedral bond decreases. The obtained ferrite nanoparticles have good magnetization as shown by VSM (in the range from 36 to 67 emu/g). Magnetic nanoparticles CoxZn1-xFe2O4 were also tested for induction heating with electromagnetic field. The sample with x (Co) = 0.4 has the highest specific absorption rate. The synthesized samples were tested as adsorbents using the Congo Red dye as model pollutant. The best adsorbent was pure zinc ferrite with the adsorption capacity of 24.7 mg/g. The catalytic activity of the obtained ferrites for the decomposition of H2O2 was studied as well. The most active catalyst was pure cobalt ferrite. Probably, the active centers are octahedral cobalt ions. Thus, the obtained magnetic nanoparticles can be used for the adsorptive removal of pollutants, catalytic decomposition of the H2O2 and low-frequency hyperthermia.

Role of Praseodymium Addition in the Microstructure and Magnetic Properties of ZnCo Ferrite Nanopowders: Positive or Negative?

IIn order to investigate the effect of Pr addition on the microstructure and magnetic properties of cobalt-zinc ferrite nanoparticles (NPs), different values of Pr element (x=0.2, 0.4 and 0.6) were added to the initial composition (Co0.6Zn0.4Fe2-xPrxO4) in the co-precipitation method, and the prepared precipitates calcined at 750 °C for 2 h. The synthesized powders were characterized by X-ray diffraction (XRD), field emission electron microscopy (FESEM), Fourier transform infrared spectroscopy (FTIR), and vibrating sample magnetometer (VSM). XRD pattern revealed the formation of a secondary phase of Pr-Fe oxide in addition to the ZnCo ferrite phase in the samples. FESEM images showed changes in the morphology and size of the particles by adding Pr to the composition. For specimen with x=0.2, the homogeneous spherical like particles with the size about less than 60 nm was formed. Whereas, for composition containing x=0.6 of Pr, a non-uniform powder with plate like particles was obtained and NPs had a thickness of approximately less than 30 nm. VSM analysis indicated that by increasing the element Pr to the cobalt-zinc ferrite composition, especially for values higher than x=0.2, the powder become a completely non-magnetic material.

Use of Dextran-Coated Cobalt–Zinc Ferrite Nanoparticles to Improve Image Quality in Magnetic Resonance Imaging: Non-Clinical Approach

Use of Dextran-Coated Cobalt–Zinc Ferrite Nanoparticles to Improve Image Quality in Magnetic Resonance Imaging: Non-Clinical Approach

Investigation of forced convective heat transfer with magnetic field effect on water/ethylene glycol-cobalt zinc ferrite nanofluid

In this work, the magnetic field effect on the convective heat transfer (CHT) properties of nanofluids comprising cobalt–zinc ferrite nanoparticles were experimentally studied. The nanofluid was prepared by dispersing the cobalt–zinc ferrite nanoparticles in the water and ethylene glycol mixture (80:20) and subjected to heat transfer studies. The experiment result exhibited that the CHT coefficient increased with the increase in the nanofluid concentration. The maximum CHT coefficient exhibited at a concentration of 0.2 wt%, which was improved by about 23.9%. It was also found that the CHT coefficient at a magnetic field of 750 G was increased by about 2.64% compared to that at 0 G for 0.2 wt% cobalt–zinc ferrite nanofluid concentration. The nanofluid with 0.2 wt% cobalt–zinc ferrite concentration exhibited the maximum CHT coefficient and pressure drop increase rate by 17% when the magnetic field was increased from 0 to 750 G.

To study the surface modified cobalt zinc ferrite nanoparticles for application to magnetic hyperthermia

In the present work, we have studied the influence of the annealing temperature and concentration of Co0.5Zn0.5Fe2O4 nanoparticles as a heat generation material for hyperthermia therapy. Cobalt zinc ferrite (Co0.5Zn0.5Fe2O4) nanoparticles were synthesized by the chemical co-perception method and annealed at 200 °C, 400 °C, and 600 °C for 3 h. The structural characterization was carried out using an x-ray diffractometer, and all samples exhibit a single-phase spinel structure. The M-H loop of the as-dried and annealed samples revealed a narrow “S” shaped hysteresis cycle, which exhibits the superparamagnetic behavior of all samples. The Mössbauer spectrum of all samples at room temperature showed a doublet, which is the signature of the superparamagnetic nature, and it is in good agreement with the acquired M-H curves. Surface modifications of the as-dried and annealed nanoparticles were achieved by coating the nanoparticles with chitosan, and solutions of different concentrations (1 mg/ml, 2 mg/ml, 4 mg/ml, and 6 mg/ml) were prepared. Employing dynamic light scattering measurement, the hydrodynamic diameter of the chitosan-coated nanoparticles at 37 °C was found to be between 173 nm and 231 nm, and the polydispersity index was less than 0.30 for all concentrations. The induction heating measurements indicated that the heating efficiency of chitosan-coated nanoparticles increased according to the order of annealing temperature (600 °C &amp;gt; 400 °C &amp;gt; 200 °C&amp;gt; as-dried) and the solution of concentration (6 mg/ml &amp;gt; 4 mg/ml &amp;gt; 2 mg/ml &amp;gt; 1 mg/ml).

THERMAL PROPERTIES OF PSS COATED COBALT ZINC FERRITE NANOPARTICLES SYNTHESIZED BY CO-PRECIPITATION METHOD

In this work Cobalt Zinc Ferrite nanoparticles Co1-xZnxFe2O4 for x = 0.25, 0.5 and 0.75 were synthesized via coprecipitation method. Annealing of all the samples was carried out at 700 ºC for 5 hours. To investigate the crystal structure XRD analysis was used which confirmed the ferrite structure of synthesized samples. Afterwards surface coating of all the samples was done by biocompatible polymer PSS. Surface functionalization of magnetic nanoparticles with PSS (Polystyrene Sulphonate) was confirmed by FTIR spectrum of samples from 2000 cm-1 to 4000 cm-1 . Thermal properties and temperature variation with oscillating magnetic field was investigated by RF induction method. That showed increasing temperatures with decreasing concentration of Zinc content.Also Increase in temperature was observed directly related to the frequency of applied magnetic field and concentration of Cobalt in the sample. SAR values for the sample were estimated using specific heat of samples and temperature slope and it was observed that SAR is directly related to cobalt content as well as inversely to the Zn content in the samples.

Synthesis, Characterization and MRI Application of Cobalt-Zinc Ferrite Nanoparticles Coated with DMSA: An In-vivo Study

The aim of this study was to synthesize and characterize the dimercaptosuccinic acid (DMSA) cobalt–zinc (Co–Zn) ferrite magnetic nanoparticles (NPs) and their efficiency as a contrast agent in in vivo MR imaging of rat liver. Co–Zn ferrite NPs were synthesized by the thermal decomposition method and stabilized by DMSA. The NPs were characterized by different analyses to study their physical and magnetic properties and were injected into 6 adult male rats. Liver MRI was performed to measure the signal intensity at different times. The average nanoparticle size was estimated at about 8 ± 1 nm using transmission electron microscopy (TEM). The r2 and r2* relaxivity of these particles were obtained at 32.85 and 168.96 mmol L−1 s−1, respectively, using an agarose phantom imaged by MRI. In the in vivo condition, injection of SNPs (2.5 mg Fe/kg) showed negative contrast in a way that for T2 and T2* weighted the maximum contrast enhancement was 58.46 and 77.13%, respectively. Regarding our results, the synthesized Co–Zn ferrite NPs stabilized by DMSA are appropriate agents for increasing the contrast in both T2 and T2* weighted based on MR imaging in rat liver.

A systematic study of cobalt-zinc ferrite nanoparticles for self-regulated magnetic hyperthermia

Cobalt-zinc ferrite nanoparticles having composition Co1-xZnxFe2O4 were processed by sol-gel method with particle sizes ranging from 10.8 nm to 3.6 nm. The crystal structure, particle size, and magnetic properties were investigated by XRD, FTIR, TEM, and VSM techniques. Single domain nature was established from the coercivity versus particle size curve. The dependence of specific saturation magnetization with zinc concentration was discussed in terms of site occupancy of cations and supported by FTIR measurements. A few single domain nanoparticle compositions exhibiting low Curie temperatures and reasonably good magnetization were subjected to induction heating measurement to explore the possibility of using the materials for magnetic hyperthermia. The material, having the composition, Co0.37Zn0.63Fe2O4 was shown to be an excellent candidate for conducting hyperthermia study with self-regulated temperature at 46 °C.

Magneto-optical properties of rare earth metals substituted Co-Zn spinel nanoferrites

Cobalt–zinc ferrite nanoparticles (NPs) substituted with three different metals, Co0.5Zn0.5RexFe2-xO4 (RE = Ce, Dy, and Y; 0.00 ≤ x ≤ 0.05) were prepared hydrothermally. Fourier Transform-Infrared (FT-IR) Spectroscopy, X-ray powder diffraction (XRD), Field-Emission Scanning Electron Microscope (FESEM) coupled with energy-dispersive X-ray spectroscopy (EDX) and Vibrating Sample Magnetometry (VSM) analyzed the products. The formation of cubic phase of spinel Co-Zn ferrite NPs were confirmed through XRD, FT-IR and FE-SEM techniques. The structural investigation of NPs by XRD revealed that the lattice parameter "a" decreases with the introduction of the RE in the ferrite structure by the substitution of Fe3+ by RE ions. The different magnetic parameters of Co0.5Zn0.5RexFe2-xO4 (RE = Ce, Dy, and Y; 0.00 ≤ x ≤ 0.05) NPs such as the saturation magnetization, coercivity, remanence, and magnetic moment were calculated and discussed in relation to structure and microstructure properties. M (H) hysteresis curves indicated that the samples exhibit superparamagnetic nature at room temperature. A slight improvement in the magnetization was obtained especially for the Ce- and Y-substituted Co0.5Zn0.5Fe2O4 (CZF) NPs at a certain RE level. However, the case Dy-substituted CZF products showed a sharp decrease in the magnetization with x > 0.01. The results are mostly ascribed to the substitution of smaller Fe3+ ions with larger RE3+ ions.

Synthesis of polymer coated Co0.5Zn0.5Fe2O4 nanoparticles and their enhanced anticancer activity against HepG2 cell line

Cobalt zinc ferrite nanoparticles with stoichiometry Co0.5Zn0.5Fe2O4 (CZFN) were synthesized by sol-gel method with high colloidal stability having room temperature ferromagnetism. For biological applications, CZFN were transferred to aqueous phase by polymer coating with amphiphilic polymer, whereas fluorescent dye (ATTO-590) was used as model system for anti-cancer drug loaded polymer shell. The amount of functional molecule varied up to 25% of the anhydride rings, which provides greater affinity of drug loading in polymer shell. CZFN were characterized by x-ray diffraction, Fourier transformed infrared spectroscopy, UV–vis absorption spectroscopy, gel electrophoresis and vibrating sample magnetometer. The in vitro cytotoxicity of CZFN was examined against HepG2 which revealed that CZFN (IC50:3.01 nM) strongly inhabits growth of the cells. Further the particles did not induce any significant hemolysis. Stimulatingly, this seems to be a noteworthy improvement towards the ability of surface functionalized multifunctional CZFN as carriers for drugs for anti-cancer therapy and their use as nanomedicine.

Structural and Magnetic Properties of Cu2+ Substituted Co–Zn Ferrite Nanoparticles, Synthesized by Sol–Gel Combustion Method

In this work, the effect of Cu content on structural and magnetic properties of Cobalt–Zinc Ferrite nanoparticles synthesized by sol–gel combustion method have been investigated. All the samples exhibit cubic spinel structure and the lattice constant decreases linearly with increasing Cu-content. Average crystallite sizes calculated from Debye–Scherrer formula are in the range of 51–100 nm. The broadening of X-ray diffraction peaks decrease with increasing Cu content ‘x’ suggest that crystallite size increases with increasing ‘x’. Cation distribution estimated form X-ray line intensity calculations show that Cu ions simultaneously occupy tetrahedral (A) and octahedral (B) sites with different ratio and Zn and Co ions occupies A and B sites respectively. With increasing Cu content a fraction of Co ions migrate to A site when x >0.2. Grain sizes estimated from SEM are found to be increase with increasing Cu content. Particle size calculated using TEM for the undoped Co–Zn ferrites is about 55 nm. Saturation magnetization (Ms), Coercivity (Hc) and remanent magnetization (Mr) that varies significantly with Cu-Content. Saturation magnetization decreases from 90.7 emu/g (x = 0.0) to 51 emu/g (x = 0.4). The proposed cation distribution supports the variation in saturation magnetization and Coercivity with increasing Cu content.

The effect of magnetic nanoparticles on neuronal differentiation of induced pluripotent stem cell-derived neural precursors.

IntroductionMagnetic resonance (MR) imaging is suitable for noninvasive long-term tracking. We labeled human induced pluripotent stem cell-derived neural precursors (iPSC-NPs) with two types of iron-based nanoparticles, silica-coated cobalt zinc ferrite nanoparticles (CZF) and poly-l-lysine-coated iron oxide superparamagnetic nanoparticles (PLL-coated γ-Fe2O3) and studied their effect on proliferation and neuronal differentiation.Materials and methodsWe investigated the effect of these two contrast agents on neural precursor cell proliferation and differentiation capability. We further defined the intracellular localization and labeling efficiency and analyzed labeled cells by MR.ResultsCell proliferation was not affected by PLL-coated γ-Fe2O3 but was slowed down in cells labeled with CZF. Labeling efficiency, iron content and relaxation rates measured by MR were lower in cells labeled with CZF when compared to PLL-coated γ-Fe2O3. Cytoplasmic localization of both types of nanoparticles was confirmed by transmission electron microscopy. Flow cytometry and immunocytochemical analysis of specific markers expressed during neuronal differentiation did not show any significant differences between unlabeled cells or cells labeled with both magnetic nanoparticles.ConclusionOur results show that cells labeled with PLL-coated γ-Fe2O3 are suitable for MR detection, did not affect the differentiation potential of iPSC-NPs and are suitable for in vivo cell therapies in experimental models of central nervous system disorders.

Ac Magnetic Susceptibility and EPR Studies of (Co0.5Zn0.5Fe2O4) x /(Cu0.5Tl0.5)-1223 Composites

Cobalt zinc ferrite nanoparticles (Co0.5Zn0. 5Fe2O4)x (∼5–8 nm in size) added to Cu0.5Tl0.5Ba2Ca2Cu3O10−δ superconductor samples, 0.00 ≤x≤ 0.20 wt. %, were prepared using a singlestep solid-state reaction technique. The temperature dependence of the real (χ′) and imaginary (χ″) components of the magnetic susceptibility (ACMS) was measured at various ac magnetic field amplitudes (3–16 Oe). The results were analyzed by using Bean critical state model to estimate the critical current density (Jc) It was found that Jc increases as x increases up to 0.08 and then it decreases with further increase in x. X- and Q-Band (9.3 and 33. GHz) electron paramagnetic resonance (EPR) spectra were measured in the temperature range from 300 to 10 K.The g values of Cu 2+ monomer were found to correspond to that of rhombic site symmetry with gxx = 2.21 ± 0.02, gyy = 2.10 ± 0.02, and gzz = 2.02 ± 0.02.

Synthesis and magneto-electrical properties of MFe2O4 (Co, Zn) nanoparticles by oleylamine route

In this study, nearly monodisperse cobalt ferrite (CoFe2O4) and zinc ferrite (ZnFe2O4) nanoparticles (NPs) without any size-selection process have been fabricated through an alluring method in an oleylamine (OAM)/benzyl ether system. Samples were synthesized by thermal decomposition of metal acetylacetonates in a high-boiling solvent and in the presence of oleylamine as surfactant and reducing agent. XRD analysis confirmed the purity and nanosized of both products and TEM analysis showed the monodispersion of them also. The oleylamine coated nanoparticles exhibited semiconducting nature at lower frequencies i.e. conductivity enhances with temperature. The dc conductivity curves of ZnFe2O4@OAm and CoFe2O4@OAm NPs indicate significant temperature-dependent behavior. The temperature and frequency-dependent variations of dielectric loss (ε″) of MFe2O4@OAm NPs display an almost sharp exponential decrease with frequency which becomes more considerable at higher temperatures and at low at low frequency regime. From 57Fe Mössbauer spectroscopy data, the variation in line width, isomer shift, quadrupole splitting and hyperfine magnetic field values have been determined. Although the Mössbauer spectra for the ZnFe2O4@OAm consists only one paramagnetic central doublet and CoFe2O4@OAm NPs have also one paramagnetic doublet and three magnetic Zeeman sextet.

The impact of silica encapsulated cobalt zinc ferrite nanoparticles on DNA, lipids and proteins of rat bone marrow mesenchymal stem cells

Nanomaterials are currently the subject of intense research due to their wide variety of potential applications in the biomedical, optical and electronic fields. We prepared and tested cobalt zinc ferrite nanoparticles (Co0.5Zn0.5Fe2O4+γ [CZF-NPs]) encapsulated by amorphous silica in order to find a safe contrast agent and magnetic label for tracking transplanted cells within an organism using magnetic resonance imaging (MRI). Rat mesenchymal stem cells (rMSCs) were labeled for 48 h with a low, medium or high dose of CZF-NPs (0.05; 0.11 or 0.55 mM); silica NPs (Si-NPs; 0.11 mM) served as a positive control. The internalization of NPs into cells was verified by transmission electron microscopy. Biological effects were analyzed at the end of exposure and after an additional 72 h of cell growth without NPs. Compared to untreated cells, Annexin V/Propidium Iodide labeling revealed no significant cytotoxicity for any group of treated cells and only a high dose of CZF-NPs slowed down cell proliferation and induced DNA damage, manifested as a significant increase of DNA-strand breaks and oxidized DNA bases. This was accompanied by high concentrations of 15-F2t-isoprostane and carbonyl groups, demonstrating oxidative injury to lipids and proteins, respectively. No harmful effects were detected in cells exposed to the low dose of CZF-NPs. Nevertheless, the labeled cells still exhibited an adequate relaxation rate for MRI in repeated experiments and ICP-MS confirmed sufficient magnetic label concentrations inside the cells. The results suggest that the silica-coated CZF-NPs, when applied at a non-toxic dose, represent a promising contrast agent for cell labeling.

Competing crystallite size and zinc concentration in silica coated cobalt ferrite nanoparticles

Silica coated (30wt%) cobalt zinc ferrite (Co1−xZnxFe2O4, x=0, 0.2, 0.3, 0.4, 0.5 and 1) nanoparticles were synthesized by using sol–gel method. Silica acts as a spacer among the nanoparticles to avoid the agglomeration. X-ray diffraction (XRD) reveals the cubic spinel ferrite structure of nanoparticles with crystallite size in the range 37–45nm. Fourier transform infrared (FTIR) spectroscopy confirmed the formation of spinel ferrite and SiO2. Scanning electron microscopy (SEM) images show that the nanoparticles are nearly spherical and non-agglomerated due to presence of non-magnetic SiO2 surface coating. All these measurements signify that the structural and magnetic properties of Co1−xZnxFe2O4 ferrite nanoparticles strongly depend on Zn concentration and nanoparticle average crystallite size in different Zn concentration regimes.