Variation In Zn Concentration Research Articles

Liquid Metal Embrittlement Cracking in Uncoated Transformation-Induced Plasticity Steel during Consecutive Resistance Spot Welding

In the automotive production line, a single pair of electrodes is employed to produce hundreds of consecutive welds before undergoing dressing or replacement. In consecutive resistance spot welding (RSW) involving Zn-coated steels, the electrodes undergo metallurgical degradation, characterized by Cu-Zn alloying, which impacts the susceptibility to liquid metal embrittlement (LME) cracking. In the present investigation, the possibility of LME crack formation in uncoated TRIP steel joints during consecutive RSW (involving 400 welds in galvannealed and uncoated TRIP steels) was investigated. The results have shown that different Cu-Zn phases were formed on the electrode surface because of its contamination with Zn from the galvannealed coating. Therefore, during the welding of the uncoated TRIP steel, the heat generated at the electrode/sheet interface would result in the melting of the Cu-Zn phases, thereby exposing the uncoated steel surface to molten Zn and Cu, leading to LME cracking. The cracks exhibited a maximum length of approximately 30 µm at Location A (weld center) and 50 µm at Location B (shoulder of the weld). The occurrence and characteristics of the cracks differed depending on the location as the number of welds increased due to the variation in Zn content. Type A cracks did not form when the number of welds was less than 280. Several cracks with a total length of approximately 30 μm were suddenly formed between 280 and 400 welds. On the other hand, type B cracks began to appear after 40 welds. However, the number and size of these exhibited inconsistency as the number of welds increased. Overall, the results have shown that small LME cracks can form even in uncoated steels during consecutive welding of Zn-coated and uncoated steel joints.

Hydrothermal Synthesis of Cu0.66‐xZn0.34+xSe Materials and Investigation of Their Structural, Optical, and Magnetic Properties

AbstractIn the current paper, we have prepared Cu0.66‐xZn0.34+xSe materials by varying the concentration of copper and zinc (x=0, 0.085, 0.17, 0.255, 0.34) with the help of a facile one‐step hydrothermal method. The X‐ray diffraction study reveals that the as‐prepared nanomaterials show the polycrystalline property. The crystallinity increases with the variation of Zn concentration, and the average crystallite size was calculated in the 39 to 55 nm range. The morphological analysis shows the uniform and agglomerated particles having an average size of around 596 nm. High‐resolution transmission electron microscopy and selected area electron diffraction study reveal the crystalline phases of the prepared sample. The energy‐dispersive X‐ray analysis confirmed the presence of constituent elements in the sample. The sample shows a high optical bandgap in the range of 3.6 eV to 4.09 eV, which was calculated from absorbance spectra. Photoluminescence measurements of the samples were carried out with 532 nm laser excitation, where the defect‐related emission peaks in the 540–850 nm range are observed. A change in the bandgap and optical emission is observed for different compositions. The magnetic properties analysis through the vibrating sample magnetometer reveals that the prepared sample exhibits ferromagnetic behaviour at room temperature, which can be used in magnetic storage applications. The tuning of the optical properties of the samples by varying the copper and zinc concentrations will be useful for various photonic devices.

A genome-wide association study identifies a transporter for zinc uploading to maize kernels.

The Zn content in cereal seeds is an important trait for crop production as well as for human health. However, little is known about how Zn is loaded to plant seeds. Here, through a genome-wide association study (GWAS), we identify the Zn-NA (nicotianamine) transporter gene ZmYSL2 that is responsible for loading Zn to maize kernels. High promoter sequence variation in ZmYSL2 most likely drives the natural variation in Zn concentrations in maize kernels. ZmYSL2 is specifically localized on the plasma membrane facing the maternal tissue of the basal endosperm transfer cell layer (BETL) and functions in loading Zn-NA into the BETL. Overexpression of ZmYSL2 increases the Zn concentration in the kernels by 31.6%, which achieves the goal of Zn biofortification of maize. These findings resolve the mystery underlying the loading of Zn into plant seeds, providing an efficient strategy for breeding or engineering maize varieties with enriched Zn nutrition.

Effect of Zn content on microstructure and properties of hypoeutectic and near-eutectic Al-Si alloys

In this research, the microstructure and mechanical properties of permanent mould cast Al-Si (7 wt.% and 12 wt.%) alloys without and with different amounts of Zn (1 wt.%, 2 wt.% and 4 wt.%) were analysed. The Al-xSi-yZn alloys have been prepared through a stir casting process using an Al-15 wt.% Si master alloy at 800 °C. Optical microscopic analyses have revealed variation in the α-Al matrix and Si needles in the alloy with the variation in Zn content. The mechanical properties analysis has shown that the hardness, tensile strength and wear resistance of the alloys increase with the addition of Si but decrease with the addition of Zn, within the limit of the alloying additions of the present research.

Subsuming the Metal Seed to Transform Binary Metal Chalcogenide Nanocrystals into Multinary Compositions.

Direct colloidal synthesis of multinary metal chalcogenide nanocrystals typically develops dynamically from the binary metal chalcogenide nanocrystals with the subsequent incorporation of additional metal cations from solution during the growth process. Metal seeding of binary and multinary chalcogenides is also established, although the seed is solely a catalyst for nanocrystal nucleation and the metal from the seed has never been exploited as active alloying nuclei. Here we form colloidal Cu–Bi–Zn–S nanorods (NRs) from Bi-seeded Cu2–xS heterostructures. The evolution of these homogeneously alloyed NRs is driven by the dissolution of the Bi-rich seed and recrystallization of the Cu-rich stem into a transitional segment, followed by the incorporation of Zn2+ to form the quaternary Cu–Bi–Zn–S composition. The present study also reveals that the variation of Zn concentration in the NRs modulates the aspect ratio and affects the nature of the majority charge carriers. The NRs exhibit promising thermoelectric properties with very low thermal conductivity values of 0.45 and 0.65 W/mK at 775 and 605 K, respectively, for Zn-poor and Zn-rich NRs. This study highlights the potential of metal seed alloying as a direct growth route to achieving homogeneously alloyed NRs compositions that are not possible by conventional direct methods or by postsynthetic transformations.

Optical and structural properties of vacuum annealed multilayer nanostructured CdZnS thin films deposited by thermal evaporation

The CdS and multilayers of CdS and Zn thin films were deposited on glass substrates by thermal evaporation. Subsequently, deposited films were annealed under a high vacuum to diffuse Zn into CdS films. Vacuum annealed films of CdS and CdZnS (CZS) were characterized for structural, surface morphology and optical properties. The XRD results showed that films were polycrystalline with hexagonal and cubic structures having predominant diffraction corresponding to the (0 0 2) plane. It was also observed that the lattice constants decreased, grain size and bandgap increased as Zn content increases in deposited films. The transmittance of as-deposited films increased drastically by vacuum annealing up to 90% in visible and NIR regions. EDX results confirmed that the concentration of Zn increased with the increase of Zn layer thickness into the multilayer structure of CZS films. The results obtained suggest that the blue shift of the absorption edge of CZS films will be useful for enhancing the efficiency of photovoltaic cells and optoelectronic devices in this region. The results reported in this paper revealed that the refractive index, optical band gap and lattice constants of CZS films can be tailored by the variation of Zn concentration. The potential of vacuum annealing is also elaborated to diffuse metallic Zn into CdS films.

Carbonated apatite lattice parameter variation across incremental growth lines in teeth

Results of microbeam mapping (x-ray excited x-ray fluorescence and transmission x-ray diffraction) of Beluga whale cementum and of beaver dentin reveal growth bands are defined by variation in mineral content (carbonated hydroxyapatite, cAp), by variation in Zn content and by variation in cAp lattice parameter a. For both tissues, diffraction and fluorescence data show that Zn signal and a are anti-correlated, that is high Zn signal is co-located with low a, and vice versa. In cementum and bone, treatment with acid removes Ca, Zn and cAp. The data are strong evidence that Zn is incorporated into the cAp lattice in these tissues and that the amount of Zn incorporated varies across two very different types of growth bands, annual bands in Beluga cementum and daily incremental bands in beaver dentin. To the best of the authors’ knowledge, this is the first observation of spatial variation of lattice parameter within growth bands.

Zinc concentrations in Blue-footed booby (Sula nebouxii) eggs, nestlings, and adults

Zinc is essential for animal metabolism, but the variation in Zn concentrations within seabird populations has been seldom explored. We collected Blue-footed booby (Sula nebouxii) eggs during 2012 and 2013 and blood samples from nestlings and adults during 2011 and 2012 in Sinaloa, Mexico, to evaluate differences in Zn concentrations among years, ages, sexes, and breeding stages. Zinc concentrations in eggs ranged between 27.3 and 64.9 ppm (dry weight), whereas Zn levels in the blood of nestlings and adults ranged between 16.1 and 53.1 ppm (dry weight). Egg Zn concentrations did not differ due to developmental stage, although Zn concentrations were significantly higher in 2013 than in 2012. Nestling Zn concentrations differed between years and decreased gradually with age. Chicks had significantly higher Zn concentrations than those of adults. Once nestlings stopped growing, females presented higher Zn concentrations than males. Adult Zn concentrations were higher during the pre-laying period than during the other breeding stages. Our results suggest that growth, sex, and breeding stage affect blood Zn concentrations, which may be due to stage-specific requirements. When compared with those of other seabird species, the Zn concentrations reported here are intermediate, and we did not detect adverse effects on either nestlings or adults.

High zinc density groundnut cultivars: A solution to Zn malnutrition

Analysis of a number of groundnut cultivars for several years showed variation in Zn concentration in seedwith year, field and crop responsiveness to Zn fertilizers. Its concentration ranged from 21 to 67 mg/kg with a mean value of 42 mg/kg and with application of 1-2 kg Zn, increased to 24-78 mg/kg with a mean of 49 mg/kg. Twenty high Zn density groundnut cultivars with more than 50 mg/kg were identified for use as food.

In Situ Band-Edge Monitoring of Cd1−yZnyTe Substrates for Molecular Beam Epitaxy of HgCdTe

We demonstrate the benefits of in situ band-edge monitoring of CdZnTe substrates for molecular beam epitaxy (MBE). The production of large-area Cd1−yZnyTe(211)B substrates up to and exceeding 8 × 8 cm2 brings new challenges from the perspective of MBE growth of Hg1−xCdxTe. Localized variation of the Zn concentration, even less than y = 0.01, can potentially cause variation in lattice-misfit with the HgCdTe epi-layers potentially resulting in ∼ 10 × difference in etch-pit density. Variation in Zn concentration is expected to be greater over larger substrates, and thus local differences in dislocation density may also be expected. The substrate Zn concentration has been determined using in situ band-edge measurement prior to nucleation of HgCdTe. Ex situ infrared transmission spectra has been used to confirm the validity of in situ band-edge wavelength measurements. We also examine the usefulness of band-edge thermometry (BET), for monitoring substrate temperature during Te/oxide desorption and for nucleation of HgCdTe epi-layers. In principle, knowledge of the exact Zn content across the largest area of the substrate, allows for tuning growth parameters to maximize yield of perfectly lattice-matched material.

Sr/Eu cation doping and thermoelectric properties of the compound Ca<sub>9</sub>Zn<sub>4.5</sub><sub>−</sub><sub><italic>δ</italic></sub>Sb<sub>9</sub> (0<<italic>δ</italic><0.5)

Previous studies suggested that Zintl phases related to the Ca9Zn4.5− δ Sb9 (0 δ x Cu x Sb9 indicated that they could achieve an optimized zT around 0.7. Especially for Ca9Zn4.5− δ Sb9, a very recent report suggested that a high zT of 1.1 at 875 K could be obtained in combination of various secondary phases introduced by the variation of Zn contents, which provided a chemical potential to change the composition. However, to change the composition of Ca9Zn4.5− δ Sb9 is actually very difficult to implement owing to the narrow homogeneity range. In this work, with Ca substituted by big cations such as Eu2+ and Sr2+, the unit cell of Ca9Zn4.5− δ Sb9 was expanded, and similar significant enhancement on the thermoelectric performance was resulted. All syntheses were handled inside a glovebox, then the reactants were loaded in the Nb tube and arc-welded, which were enclosed in a fused silica tube. The reactions were firstly heated to 1173 K in 6 h and then maintained at this temperature for 24 h. After the homogeneity process, the furnace was slowly cooled down to 873 K at a rate of 6 K/h, followed by another dwelling for 6 hours and finally cooled down to 573 K at a rate of 10 K/h. At last, the furnace was shut down and the reactions were opened in the glovebox. The compound were fully characterized by single-crystal X-ray diffraction (SXRD) and powder X-ray diffraction(PXRD), Energy dispersive spectrometer (EDS) and Hall effect measurement, etc. Single-crystal X-ray diffraction (SXRD) proves that with the increase of Sr component, the crystal parameters are slightly increasing. Hall effect measurement show that the substitution of Ca by Eu or Sr can both lead to an obvious decreasing on the carrier (holes) concentration, and the resultant mobility for Sr/Eu-doped materials is very similar if compared by the same doping level. It is also noted that neither the carrier concentration nor the mobility seems to vary linearly with the Eu/Sr-doping contents, which means a saturated state will be eventually approached. This phenomenon is consistent with the speculation above that the changes on the properties should predominantly originate from the change of interstitial Zn content, which the size effect dominated. While the decreasing carrier concentrations as well as the increasing mobility and lattice thermal conductivity all point to a structure modification, the crystal structures of these doped materials were systematically verified through the single crystal X-ray diffraction. In conclusion, although a direct measurement on such a small composition variation is very difficult (the X-ray diffraction results prove it), the significantly reduced carrier concentration and increased mobility as well as lattice thermal conductivity can still provide some useful hints on understanding the property optimization of these materials. For material Ca8.2Eu0.8Zn4.5− δ Sb9, high figure of merit with ZT ~0.81 has been achieved at 873 K.

Influence of alloying element Zn on the microstructural, mechanical and corrosion properties of binary Mg-Zn alloys after severe plastic deformation

This work presents an analysis of the microstructural, mechanical and corrosion properties of two binary Mg-Zn alloys. Mg-6 wt%Zn and Mg-12 wt%Zn cast alloys were subjected to annealing followed by quenching and processed via equal channel angular pressing with applied back-pressure (ECAP-BP). After ECAP-BP, both alloys were thoroughly examined and showed partially recrystallized and highly deformed areas. High-angle annular dark-field imaging revealed a difference in Zn content across the α-Mg matrix of the Mg-12 wt%Zn after ECAP-BP due to the growth of MgZn2 nanoparticles. Electron energy-loss spectroscopy (EELS) was carried out to qualify an average Zn content in these areas, and a variation in Zn content up to 2at.% was found. Compression tests revealed mechanical anisotropy and a significant increase in the strength of both alloys after ECAP-BP. The yield strength, σ02, was in the range from 269 to 385MPa depending on the composition and compression axis. The initial state alloys showed yield strengths, σ02, of only 75–150MPa but improved ductility. The corrosion rates of the Mg-Zn alloys in the initial state, evaluated using a hydrogen evolution method in NaCl solution, were higher for Mg-12 wt%Zn. The corrosion rates of both alloys after ECAP-BP were higher than those of the initial state. Light microscopy observations did not reveal any preference for corrosion propagation, including transcrystalline, intercrystalline or interphase corrosion, in any of the materials.

An Investigation on the Optical Band Gap and Ac Conductivity of Mn-Zn Nanoferrites

In this paper, the behaviour of the optical band gap and ac conductivity of Mn-Zn nanoferrites with the variation of the Zn concentration is reported. It was observed that in spite of a slight increase in the optical band gap, ac conductivity increases with the increase in Zn concentration. The observed behaviour has been explained in terms of the dominating factor which plays a key role in determining its properties. Optical band gap has a strong dependence on the crystallite size while the ac conductivity depends on the availability of the charge carriers for conduction and applied frequency. With the variation in Zn concentration, the above-mentioned important factors change which affect both the properties. A comparative examination of the optical band gap and ac conductivity of the prepared samples clearly gives support to the hopping of the charge carriers as the conduction mechanism in ferrites.

Effect of intermetallic compounds on mechanical properties of copper joints ultrasonic-soldered with Sn-Zn alloy

The transformation of the intermetallic compounds (IMC) at the interface of Sn-Zn solder and Cu substrate by an ultrasonic-assisted soldering method with the variation of Zn content was investigated. The formation of IMC at the solder/Cu interface is controlled by the Zn content in the filler metals. The IMC layer of Cu6Sn5 forms if the mass fraction of Zn is lower than 0.5wt.%. The IMC becomes a single-layered Cu5Zn8 if the mass fraction of Zn exceeds 1wt.%. The layer of Cu5Zn8 thickens with the increase of Zn content. Joints with an IMC layer of Cu5Zn8 exhibit a higher strength than that with Cu6Sn5. In the joints soldered with the Sn-0.5Zn filler metal, fractures occur inside the Cu6Sn5 IMC grains. In the joints with the Zn content higher than 1wt.%, fractures propagate along the Cu5Zn8 IMC/solder interface. The locations of the fracturing are associated with the micro-cracks that existed at the IMC grains.

Variability in concentrations of zinc in serum and feed when using zinc oxide as a supplement for the prevention of facial eczema

AIMS: To determine the variability of concentrations of Zn in feed, when used as a supplement to prevent facial eczema, and to determine the variability in concentrations of Zn in serum between cows and herds that are being supplemented with ZnO in feed, using in-shed feeders or on a feed pad.METHODS: Sixteen commercial dairy farms in the Waikato region of New Zealand were enrolled, that were supplementing cows with ZnO in the feed using either an automatic in-shed feeder (ASF) or a feed pad (FP) using a feed-out or mixer wagon. On each farm 10 cows were selected by the farmer, that were assumed to be representative of the age and liveweight of the herd. Four hours after supplement feeding, each cow was weighed and a blood sample collected for measurement of concentrations of Zn in serum. Three samples of feed were collected from each farm for Zn analysis, from the beginning, middle and end of the feed being distributed. Levene’s test for homoscedasticity was used to analyse whether there were differences in variation of individual concentrations of Zn in serum, and in the feed, between the two feeding systems. Multivariable linear regression was used to examine associations between age, feeding method or liveweight and concentrations of Zn in serum, after accounting for the variability between farms.RESULTS: Of the 163 cows sampled, concentrations of Zn in serum were between 20–35 µmol/L in 75/163 (46 (95% CI=38–54)%) cows; were <20 µmol/L in 71/163 (44 (95% CI=36–52)%) cows, and >35 µmol/L in 17/163 (10 (95% CI=6–16)%) cows. The variation in concentrations of Zn in serum in individual cows differed between farms (p<0.001), and the variability was greater for cows fed using a FP than ASF (p<0.001). There was no difference in the variation of concentrations of Zn in feed between the two feeding methods (p=0.54), but concentrations of Zn in serum were associated with the amount of Zn offered in feed (p=0.008).CONCLUSIONS AND CLINICIAL RELEVENCE: There was significant variability between farms in the concentrations of Zn in the serum of cows being supplemented with ZnO in feed. Only 46% of cows sampled had concentrations of Zn between 20–35 µmol/L. Effective management of facial eczema should include monitoring Zn in the feed and in serum to ensure cows are receiving the correct dose they require.

Variation of Zn content in soils under different land-use types in the Hetao oasis, Inner Mongolia of China

Understanding the status and distribution of the micronutrient Zn in soils is important for managing plant growth and preventing soil pollution for agricultural irrigation systems in arid and semi-arid regions. In this study, a total of 195 soil samples from five soil layers (0–20, 20–40, 40–60, 60–80 and 80–100 cm) in the three land-use types (wasteland, forestland and cropland) after long-term agricultural fertilization and irrigation with Yellow River water were collected in the middle of the Hetao oasis, i.e. the Yongji irrigation sub-oasis. We analyzed the vertical and spatial distributions of Zn content and its relationship with soil properties to determine whether differences of Zn content existed in the soil profiles. The results revealed that the mean content of Zn was 107 mg/kg, 1.9 times higher than the background value (55.7 mg/kg) of the Hetao oasis and much lower than the secondary standard value (300 mg/kg) of the Chinese Environmental Quality Standard for Soils when pH>7.5. Soil Zn contents were not significantly different and the coefficients of variation of Zn contents were less than 50% in the five soil layers. Soil Zn content was similar from southern to northern parts but increased from western to eastern parts in the sub-oasis. Soil Zn contents did not differ significantly among the three land-use types, but soil total nitrogen (TN) contents were significantly higher in the agriculturally managed forestland and cropland than in the wasteland (P<0.05). Zn was significantly and positively correlated with TN (F=36.6, P<0.001). The use of fertilizers may increase the content of Zn in soils, but flooding irrigation may minimize the differences in the spatial distribution of soil Zn content in the whole sub-oasis. This research is of important value for soil pollution control and sustainable land use management in arid and semi-arid regions.

Temporal and spatial variations in the proximate composition, amino acid, and mineral content of Pyropia yezoensis

Temporal and spatial variations in the proximate composition, amino acid content, and mineral content of Pyropia yezoensis were evaluated at Jindo, Haenam, and Seochun on the southern and western coasts of Korea. The proximate composition of P. yezoensis showed a specific pattern where carbohydrate, lipid, and ash increased over time, while protein decreased over time from January to April. Amino acids from P. yezoensis, such as alanine, aspartic acid, glutamic acid, leucine, and glycine, as well as 14 different minerals, were identified. Among them, aspartic acid, alanine, and glutamic acid were present at the highest concentrations. The concentration of alanine ranged from 3.40 ± 0.22 to 0.97 ± 0.07 g (100 g)−1 at all sites. Five macro minerals (Ca, K, Mg, Na, and P) and seven micro minerals (Mn, Co, Fe, Ni, Cu, Zn, and Cr) were measured at three different sites. The macro mineral K was present at the highest concentration, followed by P, Na, Ca, and Mg. The concentration of K showed spatial and temporal variations. P. yezoensis at Haenam contained 3249.39 ± 100.82 mg (100 g)−1 in January, but decreased to 55.39 ± 209.95 and 426.00 ± 389.74 mg (100 g)−1 in February and March, and then increased to 2120.42 ± 454.53 mg (100 g)−1 in April. The micro mineral, Fe, was present at the highest concentrations, followed by Zn and Co. The concentration of Fe ranged from 42.71 ± 57.23 to 12.08 ± 1.55 mg (100 g)−1 in March and April at Haenam. The concentration of Zn was highest in January and then gradually decreased from February to April, while Jindo and Haenam did not show spatial and temporal variations in Zn concentrations. In this study, temporal and spatial variations in the proximate composition, amino acid content, and mineral content of Pyropia were determined to analyze the protein, amino acid, lipid, carbohydrate, and mineral contents, which showed temporal and spatial variations during cultivation from October to April.

Genetic variability for 65Zn uptake and transport in leaves and roots of rice (Oryza sativa L.) genotypes

Based on seed and leaf zinc (Zn) content, contrasting rice genotypes were identified from the previous study. To know the relationship between uptake and translocation in rice, an experiment was conducted using radio labelled 65 Zn with these selected genotypes in hydroponic solution culture containing radioactive 65 Zn. Plants were harvested 6, 24 and 48 hrs after the treatment imposition. Activity of 65 Zn was estimated using liquid scintillation counter. Zinc uptake was measured both in leaf and root samples. High Zn types showed high uptake compared to low Zn types. The shoot content was also high in high types. It can be inferred that the observed genotypic variation in Zn content was predominantly due to differences in uptake of Zn by roots. After 24 hrs after exposing the seedlings to 65 Zn, the root Zn content was almost twice high in high Zn types compared to low Zn types. These results indicate that variability in Zn levels is attributed to differences in 65 Zn uptake subsequent to its transport to shoot.

Determination of zinc in rice grains using DTZ staining and ImageJ software

Dithizone (DTZ) staining is a rapid, simple, and inexpensive method that allows the histochemical localization of Zn. In this study, we evaluated genotypic variation in Zn concentration in brown rice grown in the field using atomic absorption spectrophotometer (AAS) as DTZ staining quantified using ImageJ software. We used dehusked grains from upland rice accessions widely cultivated in Brazil. The DTZ staining showed that the concentration of Zn varied within and between rice grains. The staining intensity index (Y) provided differences in localization of Zn across the grain regions. Zn concentration in brown rice varied in multiple regression analysis, showing major differences in index weighted by stained area of each region (YAW) for the embryo, endosperm, and aleurone, especially in the endosperm and aleurone regions due to a large portion of the area in the kernel. The total YAW among rice accessions was positively correlated with Zn concentration in grains by chemical analysis. The DTZ staining associated with imageJ software is a promising to estimate Zn concentration in different grain tissues. Thus, this method may be useful for rapid screening of rice germplasms.

Grain size effects on the magnetic properties of ZnxMn1−xFe2O4 nanoferrites

Abstract Single phase nanoferrites bearing the chemical formula ZnxMn1−xFe2O4 (0≤x≤1.0) have been produced under low reaction temperature of 200 °C. The compounds were characterized by X-ray diffraction, Mossbauer and SQUID measurements. The particle size varies between 5 nm and 14 nm. The particle size dependence of the magnetic properties is investigated. Our results indicate spin-glass behavior at temperatures between 100 K and 200 K. The variation of Zn concentration has also significant effects on the structural and magnetic properties. The complex variation of lattice parameter with x is explained on the basis of redistribution of Zn atoms in both tetrahedral (A) and octahedral (B) sites. The 57Fe Mossbauer effect spectra show paramagnetic spin state in all the compounds.