Mossbauer Spectroscopy Research Articles

Unveiling the Hidden Entropy in ZnFe2O4.

The antiferromagnetic (AFM) transition of the normal ZnFe2O4 has been intensively investigated with results showing a lack of long-range order, spin frustrations, and a “hidden” entropy in the calorimetric properties for inversion degrees δ ≈ 0 or δ = 0. As δ drastically impacts the magnetic properties, it is logical to question how a δ value slightly different from zero can affect the magnetic properties. In this work, (Zn1-δFeδ)[ZnδFe2-δ]O4 with δ = 0.05 and δ = 0.27 have been investigated with calorimetry at different applied fields. It is shown that a δ value as small as 0.05 may affect 40% of the unit cells, which become locally ferrimagnetic (FiM) and coexists with AFM and spin disordered regions. The spin disorder disappears under an applied field of 1 T. Mossbauer spectroscopy confirms the presence of a volume fraction with a low hyperfine field that can be ascribed to these spin disordered regions. The volume fractions of the three magnetic phases estimated from entropy and hyperfine measurements are roughly coincident and correspond to approximately 1/3 for each of them. The “hidden” entropy is the zero point entropy different from 0. Consequently, the so-called “hidden” entropy can be ascribed to the frustrations of the spins at the interphase between the AFM-FiM phases due to having δ ≈ 0 instead of ideal δ = 0.

Magnetic phase diagram, phase transitions, and cation distribution in Pb1-xBax(Fe0.5Nb0.5)O3 perovskites

The 57Fe-enriched polycrystalline perovskite samples Pb1-xBax(Fe0.5Nb0.5)O3, x = 0.25, 0.5, 0.75 were prepared by a solid-state synthesis and studied in detail by X-ray powder diffraction (XRD), neutron diffraction, measurement of magnetic properties, Mössbauer spectroscopy (MoS), and nuclear magnetic resonance (NMR) in a wide temperature range. The temperature dependences of hyperfine, structural, and magnetic parameters were obtained, with particular attention to their values during magnetic and structural transitions. Relatively broad transitions to antiferromagnetically ordered state were observed in all samples. Néel temperatures TN were determined from the MoS spectra, the spin-glass transition was deduced from the characteristic behavior of the temperature dependences of ZFC/FC susceptibilities and remanent magnetization. Introduction of Ba into the structure gradually disrupts the long-range AFM order present in Pb(Fe0.5Nb0.5)O3, which leads to lowered TN and broadened transition. The magnetic phase diagram of Pb1−xBax(Fe0.5Nb0.5)O3 for the whole mixing interval Pb-Ba was obtained by combining the results of various methods.

A New Oxybarometer for Basalts Based on Olivine‐Melt Mn‐Fe2+ Exchange Coefficient and FeT/Mn Ratios in Olivine and Melt

AbstractMelt Fe3+/FeT ratios are widely used as a proxy for the oxygen fugacity (fO2) in magma systems. A particular challenge is a difficulty in quantifying the Fe2+ and Fe3+ contents, which are not easily measurable by conventional techniques. Using the Mn–Fe2+ exchange coefficient (KD) between olivine (ol) and melt (m), this study develops a novel approach to this problem using the relationship of / = 1 − * (/Mnol)/(/Mnm). The key for applying this equation is to combine well‐defined with accurate Mn and FeT analyses of olivine and coexisting melt. The Mn and FeT analyses are readily measured by electron microprobe. To define , we performed experiments at 1.0–1.75 GPa and 1250–1450°C under graphite‐buffered conditions, where FeT can be used as Fe2+ to calculate . The results show that = 0.730 ± 0.025 is nearly constant over a realistic range of experimental conditions (temperature, pressure, and melt composition) relevant to basaltic magmas, allowing calculation of melt Fe3+/FeT ratios without the need for any further knowledge of these parameters. A comparison with published data, where melt Fe3+/FeT ratios have been directly measured, demonstrates that our calculation method is as accurate as Mossbauer spectroscopy and XANES techniques, thus providing a very simple and accessible approach to melt Fe3+/FeT ratio estimation. However, it should be noted that the accuracy of this method is critically reliant on: (a) accurate Mn and Fe analyses and (b) olivine‐melt chemical equilibrium.

Identification of Retained Austenite in 9Cr-1.4W-0.06Ta-0.12C Reduced Activation Ferritic Martensitic Steel

Reduced activation ferritic martensitic (RAFM) 9Cr steels, which are candidate materials for the test blanket module (TBM) of nuclear fusion reactors, are considered to be air hardenable. However, alloy composition and the processing conditions play a significant role during the transformation of austenite to martensite/ferrite on cooling. The presence of retained austenite is known to influence the mechanical properties of the steel. Identifying very low amounts of retained austenite is very challenging though conventional microscopy. This paper aims at identifying a low amount of retained austenite in normalized 9Cr-1.4W-0.06Ta-0.12C RAFM steel using synchrotron X-ray diffraction and Mossbauer spectroscopy and confirmed by advanced automated crystal orientation mapping in transmission electron microscopy. Homogeneity of austenite has been understood to influence the microstructure of the normalized steel, which is discussed in detail.

Successive Grinding and Polishing Effect on the Retained Austenite in the Surface of 42CrMo4 Steel

Low-alloy 42CrMo4 steels were studied by 57Fe Mössbauer spectroscopy (MS), X-ray diffractometry (XRD), and Energy Dispersive X-ray Spectroscopy (EDS) measurements. The investigations were performed on metallographic samples, which were subjected to a series of successive grinding and polishing with a progressively finer grit. Conversion X-ray Mössbauer spectroscopy (CXMS) was used to determine the occurrence of austenite in steel samples. It is a unique method detecting the austenite content very sensitively. Six samples with different surface preparation were investigated, starting with 4.8% of austenite on an as-cut sample, and a large decrease in the retained austenite to 2.6% was observed after the first grinding of a hardened cut sample. Additionally, an unexpectedly large decrease in the austenite content to 2.3% was found due to the final polishing. A second time applied successive grinding and polishing of all samples resulted in identical austenite content determined by CXMS of approx. 5%, which proved the applicability of the CXMS method. Generally, the result calls attention to the importance of preparation of metallurgical samples by grinding and polishing where the results can vary significantly on the level of surface processing.

Zn-=SUB=-x-=/SUB=-Fe-=SUB=-3-x-=/SUB=-O-=SUB=-4-=/SUB=- (0 ≤ x≤ 1.0) magnetic nanoparticles functionalized with polyacrylic acid (PAA)

Studies of the properties of ZnxFe3-xO4 (x=0, 0.25, 0.5, 0.75, 1.0) magnetic nanoparticles synthesized by a modified hydrothermal method are presented in comparison with the properties of the same nanoparticles stabilized with polyacrylic acid ZnxFe3-xO4@PAA. The structure, size, morphology, and magnetic properties of the samples were studied by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT IR), physical properties measurements (PPMS), and Mossbauer spectroscopy. The synthesized nanoparticles are single-phase, without additional impurities, have a narrow size distribution and are in the superparamagnetic phase. From the (XRD) measurements, it was found that with an increase in the Zn content from x=0 to x=1.0, the sizes of the nanoparticles were increasing from 17 to 33 nm. Analysis of the Mossbauer spectroscopy data showed that when doped with Zn ions from x=0 to x=1.0, the sizes of the nanoparticles were decreasing from 15 nm to 5 nm. The results of the Mossbauer studies showed that both ZnxFe3-xO4 and ZnxFe3-xO4@PAA has a core/shell type structure in which the core is magnetically ordered, whereas the shell does not have magnetic ordering. Mossbauer studies indicate that the coating of citric acid particles leads to their isolation from each other (i. e., a decrease in the thickness of the paramagnetic shell, and due to this to increasing in the diameter of the core). This (the last sentense) sentense is too long. It could be mode two or three sentences for better clarification. Keywords: ferrite-spinel nanoparticles, hydrothermal synthesis, polyacrylic acid functionalization, Mossbauer spectroscopy, properties, crystal and magnetic structure.

Structure and properties of Co-=SUB=-x-=/SUB=-Mn-=SUB=-1-x-=/SUB=-Fe-=SUB=-2-=/SUB=-O-=SUB=-4-=/SUB=- nanoparticles depending on the amount of Co ions (0≤ x≤ 1.0)

The properties of magnetic nanoparticles (MNPs) of spinel ferrites CoxMn1-xFe2O4 (at x=0.0; 0.2; 0.3; 0.4; 0.5; 0.6; 0.8; 1.0) synthesized by chemical co-precipitation method have been studied. The studies of the synthesized CoxMn1-xFe2O4 MNPs were carried out using X-ray diffraction (XRD), Raman scattering and Mossbauer spectroscopy. The results of XRD, Raman and Mossbaur studies indicate that the obtained CoxMn1-xFe2O4 MNPs are single-phase. It was established from XRD measurements that the average size of CoxMn1-xFe2O4 crystallites is 34.86 nm for MnFe2O4 (x=0) and decreases to 14.99 nm for CoFe2O4 (x=1.0) with increasing Co ions concentration. An analysis of the Mossbaur spectra showed that the average crystallite size varies from 25 nm for MnFe2O4 (x=0) to 12 nm for CoFe2O4 (x=1.0). On the Raman spectra of CoxMn1-xFe2O4 MNPs, in the region of ~620 cm-1, splitting of the A1g line is observed, which means that the studied MNPs have a reverse spinel structure. The intensity ratio of the A1g (1) and A1g (2) peaks indicates a significant redistribution of the Co2+ and Fe3+ cations between tetra- and octahedralpositions in MNPs of the CoxMn1-xFe2O4 ferrite, which is confirmed by Mossbauer data. Mossbaur spectroscopy data indicate that the synthesized CoxMn1-xFe2O4 MNPs consist of large particles with magnetic ordering and small particles in the paramagnetic phase. With an increase in the concentration of Mn ions, the proportion of fine particles increases, which leads to a decrease in the magnetic blocking temperature. The saturation magnetization of MNPs at x=0.2 (Co0.2Mn0.8Fe2O4) is 57.41 emu/g and this sample, as was found in [V. Narayanaswamy, I.A. Al-Omari, A.S. Kamzin, B. Issa, H.O. Tekin, H. Khourshid, H. Kumar, A. Mallya, S. Sambasivam, I.M. Obaidat. Nanomaterials 11, 1231 (2021)] has the highest specific absorption rate. As shown by Mossbauer studies, this is due to the fact that these particles are in a superparamagnetic state and the magnetic blocking temperature of these MNPs is in the region of ~315 K, which is most suitable for the treatment of malignant tumors by magnetic hyperthermia. Thus, the synthesized CoxMn1-xFe2O4 MNPs are promising for biomedical applications. Keywords: spinel ferrites CoxMn1-xFe2O4, magnetic structure, superparamagnetism, Mossbauer spectroscopy, materials for biomedicine.

Influence of functionalization with citric acid on the properties of magnetic nanoparticles Zn-=SUB=-x-=/SUB=-Fe-=SUB=-3-x-=/SUB=-O-=SUB=-4-=/SUB=- (0≤ x≤ 1.0)

The effect of surface functionalization with citric acid on the properties of magnetic nanoparticles (MNPs) ZnxFe3-xO4 (x=0; 0.25; 0.5; 0.75; 1.0) synthesized by the hydrothermal method was studied. To study the properties of MNPs, X-ray diffractometry (XRD) and energy dispersive X-ray spectroscopy (EDS) were used. The magnetic properties of the samples and the phase state of MNPs were studied using a physical property measurement system (PPMS) and Mossbauer spectroscopy (MS). It has been established that the sizes of crystallites and the crystal lattice parameter of ZnxFe3-xO4 MNPs change with increasing Zn2+ concentration. The low values of the coercive force and the presence of a doublet on the MS indicate the presence of both ferrimagnetic and superparamagnetic components. Keywords: ZnxFe3-xO4 ferrite spinel MNPs, hydrothermal synthesis, functionalization of MNPs with citric acid, crystal structure, magnetic properties, magnetic structure.

Магнитные наночастицы Zn-=SUB=-x-=/SUB=-Fe-=SUB=-3-x-=/SUB=-O-=SUB=-4-=/SUB=- (0 ≤ x≤ 1.0), функционализированные полиакриловой кислотой (Zn-=SUB=-x-=/SUB=-Fe-=SUB=-3-x-=/SUB=-O-=SUB=-4-=/SUB=-@ПАК)

Studies of the properties of ZnxFe3-xO4 (x=0, 0,25, 0,5, 0,75, 1) magnetic nanoparticles synthesized by a modified hydrothermal method are presented in comparison with the properties of the same nanoparticles stabilized with polyacrylic acid ZnxFe3-xO4@PAA. The structure, size, morphology, and magnetic properties of the samples were studied by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT IR), physical properties measurements (PPMS), and Mossbauer spectroscopy. The synthesized nanoparticles are single-phase, without additional impurities, have a narrow size distribution and are in the superparamagnetic phase. From the RD measurements, it was found that with an increase in the Zn content from x = 0 to x= 1.0, the sizes of nanoparticles increasing from 17 to 33 nm. Analysis of the Mössbauer spectroscopy data showed that when doped with Zn ions from x=0 to x=1.0, the sizes of nanoparticles decreasing from 15 nm to 5 nm. The results of the Mossbauer studies showed that both ZnxFe3-xO4 and ZnxFe3-xO4@PAC has a core/shell type structure in which the core is magnetically ordered, whereas the shell does not have magnetic ordering. Mossbauer studies indicate that the coating of citric acid particles leads to their isolation from each other, a decrease or elimination of interactions between particles, a decrease in the thickness of the paramagnetic shell, and, due to this, an increase in the diameter of the core.

Temperature investigations of magnetic properties when analyzing the structural phase state of a model nanocomposite with carbidosteel composition

The phase composition, magnetic state of the phases and their influence on the formation of the magnetic hysteresis properties of the nanocomposite with the (Fe0.85Mn0.10Ni0.05)83C17 composition after mechanosynthesis and subsequent annealing have been studied. It is shown that, although the dependences of the coercive force on the annealing temperature H_c(Tann) of the alloy, measured at room and liquid nitrogen temperatures, are curves with maxima, the formation of Hc is driven by different mechanisms. At room temperature measurements, the maximum Hc value of the composite is obtained when the size of the ferrite phase precipitates approaches to the critical single-domain state, whereas at low temperature maximum Hc value is caused by the change of the cementite structural state upon annealing. Keywords: Nanocrystalline Fe-C-Mn-Ni alloys, mechanical alloying, heat treatment, X-Ray diffraction, coercive force, magnetic susceptibility, Curie temperature, Mossbauer spectroscopy.

The phase composition and structure of the BiFeO-=SUB=-3-=/SUB=- film grown on MgO(001) substrate by high frequency cathode deposition in oxygen atmosphere

The crystal structure and Mossbauer spectroscopy studies results for BiFeO3 film growth on the MgO(001) single crystal substrate are present in the paper. It been shown that film have high crystal perfection and low defectiveness which results in appearing of narrow lines during the theta-2theta and φ scanning and the small (lower than 0.7o) disorientation of film and substrate crystal axes. It is been revealed that unit cell of BiFeO3/MgO(001) heterostructure possess monoclinic symmetry and deformation of unit cell is negligible. The Mossbauer study shows that magnetic subsystem of film has spatial spin-modulated structure with zero value of anharmonicity parameter (m). This indicate that at room temperature the magnetic anisotropy changes from the "easy axis" type to "easy plane" type. Keywords: thin films, bismuth ferrite, Mossbauer effect.

Фазовый состав и структура пленки BiFeO-=SUB=-3-=/SUB=-, выращенной на подложке MgO(001) методом ВЧ-катодного распыления в атмосфере O-=SUB=-2-=/SUB=-

The crystal structure and Mossbauer spectroscopy studies results for BiFeO3 film growth on the MgO(001) single crystal substrate are present in the paper. It been shown that film have high crystal perfection and low defectiveness which results in appearing of narrow lines during the θ-2θ and φ scanning and the small (lower than 0.7°) disorientation of film and substrate crystal axes. It is been revealed that unit cell of BiFeO3/MgO(001) heterostructure possess monoclinic symmetry and deformation of unit cell is negligible. The Mossbauer study shows that magnetic subsystem of film has spatial spin-modulated structure with zero value of anharmonicity parameter (m). This indicate that at room temperature the magnetic anisotropy changes from the "easy axis" type to "easy plane" type.

Zn-doped CoFe2O4Nanoparticles Synthesized Using Ginkgo Biloba Extract: Cation Distribution, Mossbauer Studies and Application for Water Treatment

The cobalt-zinc ferrites Zn1-xCoxFe2O4 (where x=0; 0.2; 0.4; 0.6; 0.8; 1.0) were obtained by green synthesis using Ginkgo Biloba extract as reductant and fuel. The cation distribution of the spinel ferrites has been investigated by means of X-ray diffraction and Mossbauer spectroscopy. The surface morphology and elemental composition were analyzed by SEM and EDS. The crystallite size decrease with increasing Co2+ content calculated from Scherrer equation and Williamson-Hall method. Adsorption properties of the spinel system were investigated using Congo Red (CR) dye as model pollutant. It is concluded that the adsorption of Congo red dye molecules can occur due to electrostatic and donor-acceptor interactions with the adsorbent surface containing various amount of active centers.

Review on Steel Enhancement for Nuclear RPVs

The reactor pressure vessel (RPV) is one of the most important elements of a nuclear power plant (NPP). The RPV determines the plant operational lifetime since it is not replaceable economically. The purpose of the RPV steel study and enhancement to increase the NPP’s (Nuclear Power Plants) operation lifetime from the original 30–40 years up to 60–80 years or even beyond. The RPV lifetime limited by ageing of the RPV steels. RPV ageing highly depends on the main environmental effects: fast neutron radiation, thermal effects causing thermal ageing and low-cycle fatigue. Firstly, the chemical composition via aged mechanical properties was studied. Efforts to increase the toughness against the radiation embrittlement was enhanced by the appearance of the modern microstructural testing devices such as APFIM (atom probe field ion microscopy), SANS (small-angle neutron scattering) positron annihilation spectroscopy (PAS), transmission electron microscopy (TEM) and Mössbauer spectroscopy (MS). The information on the effect of alloying and polluting elements for the microstructure allowed us to produce increased ageing toughness of the RPVs, and to enhance the safety and lifetime calculations of them, supporting long-term safe operation (LTO).

Characterization study and recovery of copper from low grade copper ore through hydrometallurgical route

Characterization studies were conducted on low grade copper ore with the aid of standard approaches. The Scanning Electron Microscopy-Energy Dispersive X-ray Spectroscopy (SEM-EDS) study specifies the semi-quantitative data of qualitatively analyzed chemical elements present in the ore sample. Optical Microscopy (OM) and X-Ray Diffraction (XRD) endorse the presence of chalcopyrite (CuFeS2) and pyrites along with other different mineral phases in the ore sample. Thermo Gravimetric Analysis (TGA) and Mossbauer spectroscopy studies confirm the formation of CuO and Fe2O3 after roasting at 700 °C. The better copper recovery from low grade copper ore was achieved through optimized leaching parameters. It was found that the particle size of −63+53 µm can be leached up to 94.96 % of copper using a lixiviant reagent mixture (30 vol. % hydrogen peroxide and 0.5 M sulfuric acid) under magnetic stirring for 30 min at a constant speed of 300 rpm, by keeping the liquid/solid (L/S) ratio at 20/2 ml/g. Moreover, the solvent extraction process works well with the pregnant leach solution, whereby, 98.9 % of copper extraction is possible, and the loading time is less than a minute. Meanwhile, 93.91 % of overall copper extraction efficiency was achieved through optimized leaching parameters and solvent extraction method.

Mossbauer and Raman spectroscopy study of Y-garnet particles’ magnetic properties tune-up through mechanochemically synthesized precursors

Mossbauer and Raman spectroscopy study of Y-garnet particles’ magnetic properties tune-up through mechanochemically synthesized precursors

Accurate 57Fe Mössbauer Parameters from General Gaussian Basis Sets.

The prediction of isomer shifts in 57Fe Mossbauer spectra is typically achieved by building calibration lines using the values of the density at the nuclear position. Using Slater-type orbital basis or large and specific Gaussian-type orbital basis has been thus far mandatory to achieve accurate predictions with density functional theory methods. In this work, we show that replacing the value of the density at the nucleus by the density integrated in a sphere of radius 0.06 au centered on the Fe nuclei yields excellent calibration lines (r2 = 0.976) with a high predictive power (q2 = 0.975, MAE = 0.055 mm·s–1) while using the conventional def2-TZVP basis set and X-ray geometrical parameters. Our data set comprises 69 57Fe-containing compounds and 103 signals. We also find B3LYP performing significantly better than the PW91 functional.

Photocatalytic degradation of Congo red dye using Fe-doped TiO2 nanocatalysts

Fe-doped TiO2 (2, 5, 10, 15 and 20% wt. of Fe) photocatalysts have been synthesized by sol-gel method using titanium aquacomplex precursor. The structure and morphology have been characterized by XRD, BET, SEM, and EDS analyses, Mossbauer and IR spectroscopies. XRD analysis confirmed the anatase structure. The introduction of ferric ions into the titania structure causes its amorphization. The crystallite sizes of obtained samples are around 3 nm. Fe-doped TiO2 samples possess mesoporous structure and high specific surface area (from 274 m2g-1 for 5Fe-TiO2 to 416.4 m2g-1 for 20Fe-TiO2). Mossbauer spectroscopy data confirms the incorporation of Fe3+ ions in the anatase structure. Photocatalytic degradation of Congo red dye using Fe-doped TiO2 photocatalysts was studied under the UV-A light. Optimized conditions for photocatalytic degradation of CR in the presence of hydrogen peroxide are obtained. It was found that the 2Fe-TiO2 sample in the presence of 20 mM H2O2 solution showed highest efficiency in dye photodegradation (99.4%) under UV-A light. The photodegradation kinetics was analyzed using a smartphone and fits well with first-order kinetics model.

Structurally Dependent Electrochemical Properties of Ultrafine Superparamagnetic 'Core/Shell' γ-Fe2O3/Defective α-Fe2O3 Composites in Hybrid Supercapacitors.

The paper presents a method for obtaining electrochemically active ultrafine composites of iron oxides, superparamagnetic ‘core/shell’ γ-Fe2O3/defective α-Fe2O3, which involved modifying sol-gel citrate synthesis, hydrothermal treatment of the formed sol, and subsequent annealing of materials in the air. The synthesized materials’ phase composition, magnetic microstructure, and structural, morphological characteristics have been determined via X-ray analysis, Mossbauer spectroscopy, scanning electron microscopy (SEM), and adsorption porometry. The mechanisms of phase stability were analyzed, and the model was suggested as FeOOH → γ-Fe2O3 → α-Fe2O3. It was found that the presence of chelating agents in hydrothermal synthesis encapsulated the nucleus of the new phase in the reactor and interfered with the direct processes of recrystallization of the structure with the subsequent formation of the α-Fe2O3 crystalline phase. Additionally, the conductive properties of the synthesized materials were determined by impedance spectroscopy. The electrochemical activity of the synthesized materials was evaluated by the method of cyclic voltammetry using a three-electrode cell in a 3.5 M aqueous solution of KOH. For the ultrafine superparamagnetic ‘core/shell’ γ-Fe2O3/defective α-Fe2O composite with defective hematite structure and the presence of ultra-dispersed maghemite with particles in the superparamagnetic state was fixed increased electrochemical activity, and specific discharge capacity of the material is 177 F/g with a Coulomb efficiency of 85%. The prototypes of hybrid supercapacitor with work electrodes based on ultrafine composites superparamagnetic ‘core/shell’ γ-Fe2O3/defective α-Fe2O3 have a specific discharge capacity of 124 F/g with a Coulomb efficiency of 93% for current 10 mA.

Structure, electric and thermoelectric properties of binary ZnO-based ceramics doped with Fe and Co

We have studied the interconnection between structure (grain sizes, chemical and phase composition, porosity) and some electric properties (resistivity, Hall and Seebeck coefficients, as well as power factor, concentration and mobilities of carriers) in composite ceramics (ZnO)z[(TM)xOy]1-z (TM = Fe and Co – transition metals, 0 ≤ x ≤ 3; 1 ≤ y ≤ 4, 0.5 ≤ z ≤ 10 wt%), prepared by one-step and/or two-step annealing on air of powder mixtures of ZnO and TM oxides. The structure of ceramic samples was studied by X-ray diffraction (XRD), Mossbauer (MS) and Raman (RS) spectroscopies, scanning electron microscopy (SEM), energy-dispersive X-ray (EDX) analysis and magnetometry. It was proved that phase composition of (ZnO)z[(TM)xOy]1-z ceramics depends on the type of doping agents. Addition of CoO to ZnO results in the formation of solid solutions with wurtzite structure after two-step annealing independently on Co concentration z ≤ 10 wt%. Addition of FexOy to ZnO results in the formation of the samples with three phase components after synthesis: submicron grains of wurtzute-like structure with large grains of ZnFe2O4 ferrite with spinel structure and residual oxides FexOy used as dopant in powder mixture. SEM measurements evidence that size of the wurtzite phase grains decreases from several tens of micrometers when using the one-step synthesis to a submicron level for the case of the two-step technology. Temperature dependences of electrical resistivity ρ(Т), as well as Hall and Seebeck coefficients in the undoped ZnO in th range of 6–500 K have shown a competition of the Mott and Shklovsky-Efros variable range hopping conductance (due to disordering), percolative one (due to formation of large-scaled potential relief) and a standard electron transport by Cband. It was found that Cband contribution to the carrier transport in ceramic samples (ZnO)z[(TM)xOy]1-z above 100 K was provided by both low and deep donor centers which have been formed in the wurtzite phase Zn1-δ(TM)δO. For example, in the TM doped samples we observed intrinsic shallow levels with ionization energies of about ΔE1 = (0.04–0.05) eV as well as extrinsic deep levels with ΔE2 = (0.24–0.37) eV. The iron doping of ZnO-based ceramic samples increased the room temperature Seebeck coefficient S(300 K) in average. In so doing, the S(300 K) dependence on electron concentration n of the studied samples (ZnO)z(FexOy)1-z approached maximal values (up to 1000 µV/K) at n = 1021 m−3. At the same time ZnO doping with Co resulted in more weak increase (up to 1.3–1.5 times) of S(300 K) values. Practically threefold growth of S(300 K) doe to Fe doping was attributed by us to the influence of particles of ferrite) formed in wurtzite matrix. The power factor P = (S2/ρ), estimated for the studied samples, evidenced that for both dopants it’s the highest values ( = 10−5 W/K·m) were approached in the (ZnO)z[(TM)xOy]1-z ceramics with the lowest resistivity values.