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[EN] Herein, using the auto-combustion method, a BiFeO/BiO composite was successfully synthesized for the photocatalytic degradation of nitrobenzene under visible illumination. The compound was subsequently characterized using varied characterization approaches, including XRD, SEM/EDS, FTIR, XPS, and UV–VIS techniques. The photocatalytic capability of the resulting sample was assessed by removing nitrobenzene (NB) under solar and artificial (15 W LED lamp) exposure. Within 180 and 240 min of exposure, the prepared BiFeO/BiO composite exhibited impressive photocatalytic ability with quasi-total elimination (100%) of NB under both solar and LED lights, in contrast to pure oxides. The photocatalytic capability of BiFeO/BiO was 2.88 and 1.67 folds higher than those of BiFeO and BiO. This was linked to the effective charge splitting occurring at the BiFeO/BiO interface and the lower recombination ratio of charge carriers. Additionally, BiFeO/BiO exhibited outstanding sustainability without loss of activity during the first 5 cycles. Aside from this, quenching investigation showed that OH was responsible for the degradation process. Furthermore, total organic carbon (TOC) analysis confirmed NB mineralization. Based on these previous findings, an appropriate mechanism for NB decomposition was established. Overall, the BiFeO/BiO photocatalyst is recommended for use in the efficient photocatalytic removal of organic contaminants owing to its straightforward manufacturing approach, high levels of degradation, and strong structure for potential uses.

[EN] In the context of world concern with the environment, this study aims to characterize an auto combustion produced bamboo leaf ash (BLA) by its pozzolanic behaviour, reactivity and its influence in the total porosity, pore size distribution, tortuosity and mechanical behaviour of cementitious matrices. The chemical and physical characterization of the BLA was carried using X-ray fluorescence, determination of amorphous silica content, X-ray diffraction, Fourier Transform Infrared Spectrophotometry (FTIR), laser granulometry and field emission scanning electron microscopy (FESEM). The assessed BLA is a siliceous material (74.23%) with an amorphous nature due to the amorphous silica content, which represents 92.33% of the total silica. The BLA was classified as highly reactive by assessing its pH and conductivity in a saturated calcium hydroxide (CH) medium for different proportions and temperatures. Frattini analysis, the study of CH:BLA pastes (Thermogravimetric analysis and FTIR) and Portland cement (OPC)/pozzolan pastes (Thermogravimetric analysis and FESEM) are in agreement with this classification. The replacement of OPC by BLA improved the mechanical behaviour of the cementitious matrices, as well their durability. All the mortars containing BLA presented very similar compressive strength to a control mortar (100% OPC) after only 3 days of curing and at the following tested curing ages: 7, 28 and 90 days. In the mercury intrusion porosimetry analysis, the pastes with 20 and 30% BLA content presented higher tortuosity or fewer connected pores than the control paste. Thus, the auto-combustion method proved to be successful and BLA is a suitable alternative for sustainable high-performance matrices. (C) 2019 Elsevier Ltd. All rights reserved.

[EN] In the context of world concern with the environment, this study aims to characterize an auto combustion produced bamboo leaf ash (BLA) by its pozzolanic behaviour, reactivity and its influence in the total porosity, pore size distribution, tortuosity and mechanical behaviour of cementitious matrices. The chemical and physical characterization of the BLA was carried using X-ray fluorescence, determination of amorphous silica content, X-ray diffraction, Fourier Transform Infrared Spectrophotometry (FTIR), laser granulometry and field emission scanning electron microscopy (FESEM). The assessed BLA is a siliceous material (74.23%) with an amorphous nature due to the amorphous silica content, which represents 92.33% of the total silica. The BLA was classified as highly reactive by assessing its pH and conductivity in a saturated calcium hydroxide (CH) medium for different proportions and temperatures. Frattini analysis, the study of CH:BLA pastes (Thermogravimetric analysis and FTIR) and Portland cement (OPC)/pozzolan pastes (Thermogravimetric analysis and FESEM) are in agreement with this classification. The replacement of OPC by BLA improved the mechanical behaviour of the cementitious matrices, as well their durability. All the mortars containing BLA presented very similar compressive strength to a control mortar (100% OPC) after only 3 days of curing and at the following tested curing ages: 7, 28 and 90 days. In the mercury intrusion porosimetry analysis, the pastes with 20 and 30% BLA content presented higher tortuosity or fewer connected pores than the control paste. Thus, the auto-combustion method proved to be successful and BLA is a suitable alternative for sustainable high-performance matrices. (C) 2019 Elsevier Ltd. All rights reserved.

Bizmut-ferit (BiFeO3) ispoljava jedinstvena svojstva koja pre svega doprinose teorijskom shvatanju električnih i magnetnih uređenja i njihove interakcije u kristalnim oksidnim materijalima, ali bi uz prevazilažanje trenutno postojećih prepreka materijala na bazi bizmut-ferita mogli naći primenu u mnogim oblastima. Postoji samo nekoliko jednofaznih materijala kojima se može pripisati više feroičnih svojstava (feroelektrična, feroelastična, (anti)feromagnetna) na temperaturama višim od 50 K. Zbog toga ne čudi da je baš bizmut-ferit, koji i na temperaturama iznad sobne može ispoljiti feroelektričnost, feroelastičnost, pa čak i slab feromagnetizam (iako je po magnetnoj strukturi antiferomagnetan), predmet istraživanja brojnih naučnih radova iako i dalje ne postoje uređaji koji u sastavu sadrže bizmut-ferit..., Bismuth ferrite (BiFeO3) theoretically possesses very peculiar properties, and understanding them may be the key of understanding the nature of interaction between electrical and magnetic orderings in crystalline oxides. If problems in exhibiting those properties were overcome, bismuth ferrite-based materials might be widely applicable. Few single phase materials exhibit two or three of the ferroic properties (ferroelectric, ferroelastic, (anti)ferromagnetic) at temperatures above 50 K. Being ferroelectric, ferroelastic and even weakly ferromagnetic (although possessing antiferromagnetic structure of magnetic spins) at temperatures well above the room temperature, bismuth ferrite is the subject of hundreds of scientific studies with good reason, although its application is still far from being realized...

Di-phase ceramic composites, with general formula xNi(0.7)Zn(0.3)Fe(2)O(4) - (1-x)BaTiO3(x = 0.9, 0.7, 0.5, 0.3, 0.1), were prepared by a mixing method. X-ray analysis, for powder and ceramics, indicated the formation of ferrite and barium titanate phases without the presence of the impurities. SEM analysis indicated that the composite morphology contained two types of grains, polygonal and rounded. Homogeneous microstructure and the smallest grain size were obtained in ceramics with 70% of barium titanate. The electrical properties of these materials were investigated using impedance spectroscopy, dielectric and ferroelectric measurements. The NZF-BT(30-70) composite has shown better electrical properties in comparison to other investigated ceramics, confirmed by dielectric and ferroelectric data analysis. Saturation magnetization and coercive field decreased with the increase of the content of ferroelectric phase.

Bizmut-ferit (BiFeO3) ispoljava jedinstvena svojstva koja pre svega doprinose teorijskom shvatanju električnih i magnetnih uređenja i njihove interakcije u kristalnim oksidnim materijalima, ali bi uz prevazilažanje trenutno postojećih prepreka materijala na bazi bizmut-ferita mogli naći primenu u mnogim oblastima. Postoji samo nekoliko jednofaznih materijala kojima se može pripisati više feroičnih svojstava (feroelektrična, feroelastična, (anti)feromagnetna) na temperaturama višim od 50 K. Zbog toga ne čudi da je baš bizmut-ferit, koji i na temperaturama iznad sobne može ispoljiti feroelektričnost, feroelastičnost, pa čak i slab feromagnetizam (iako je po magnetnoj strukturi antiferomagnetan), predmet istraživanja brojnih naučnih radova iako i dalje ne postoje uređaji koji u sastavu sadrže bizmut-ferit..., Bismuth ferrite (BiFeO3) theoretically possesses very peculiar properties, and understanding them may be the key of understanding the nature of interaction between electrical and magnetic orderings in crystalline oxides. If problems in exhibiting those properties were overcome, bismuth ferrite-based materials might be widely applicable. Few single phase materials exhibit two or three of the ferroic properties (ferroelectric, ferroelastic, (anti)ferromagnetic) at temperatures above 50 K. Being ferroelectric, ferroelastic and even weakly ferromagnetic (although possessing antiferromagnetic structure of magnetic spins) at temperatures well above the room temperature, bismuth ferrite is the subject of hundreds of scientific studies with good reason, although its application is still far from being realized...

U ovoj doktorskoj disertaciji ispitivana su magneto-električna svojstva kompozitnih materijala koji se sastoje od magnetne faze, nikl-cink ferita, i feroelektrične faze, barijum titanata u razlicitim masenim odnosima. Maseni odnosi ovih faza su menjani u cilju dobijanja kompozitnog materijala dobrih magnetnih i električnih svojstava. Prahovi čistih polaznih materijala, nikl ferita i barijum titanata sintetisani su hemijskom metodom auto–sagorevanja. Ova metoda predstavlja važnu tehniku za sintezu kompozita, legura, katalizatora, itd. Danas metoda auto-sagorevanja čini veoma popularan pristup za pripremu nanomaterijala koji su našli industrijsku primenu u mnogim zemljama. Prahovi nikl ferita i nikl cink ferita su dobijeni kalcinacijom prekursora na temperaturi od 1000 °C tokom 1h dok je kalcinacija barijum titanata vršena na od 900 °C tokom 2h. Prahovi kompozita dobijeni su homogenizacijom prahova nikl ferita, nikl cink ferita sa prahom barijum titanata u izopropanolu kao medijumu za mlevenje i u planetarnom mlinu u trajanju od 24 h. Dobijeni prahovi su presovani i sinterovani na različitim temperaturama. Izvršena je optimizacija procesa sinterovanja kojom su određene temperature sinterovanja svakog kompozita pojedinačno u intervalu od 1120-1200 °C u cilju dobijanja najveće gustine keramičkih uzoraka. Karakterizacija dobijenih keramičkih kompozita vršena je različitim fizičko hemijskim metodama analize. Metodom rendgenske difrakcije praćen je fazni sastav dobijenih prahova i keramike i na osnovu XRD dijagrama određene su optimalne temperature sinterovanja. Morfologije čestica praha čistog nikl cink ferita i barijum titanata određene su na osnovu analize mikrofotografija dobijenih skenirajućom elektronskom mikroskopijom. Analizom je utvrđeno da se prah nikl cink ferita sastoji od individualnih čestica sfernog oblika, koje su malih veličina (< 200 nm). Čestice praha barijum titanata su veličine oko 100 nm, a njihov oblik čestica je takođe sferan. Analizom SEM mikrograf, In this doctoral dissertation magneto-electric properties of composite materials consisting of magnetic nickel zinc ferrite phase and ferroelectric barium titanate phase in different mass ratios were investigated. Mass ratios of these phases were differed in order to obtain composite materials with optimal magnetic and electrical properties. Powders of pure starting materials, nickel zinc ferrite and barium titanate were synthesized by the chemical auto-combustion method. This is important technique for the synthesis of composites, alloys, catalyst, etc. In the present time the auto-combustion method is becoming rather popular method for the preparation of nano materials with industrial application in many countries. Powders of nickel ferrite and nickel zinc ferrite were obtained by the calcination of precursors at the temperatures of 1000 °C with duration of 1h, while the calcination of barium titanate was conducted at 900 °C for 24h. Powders of composites were obtained by homogenization of nickel ferrite and nickel zinc ferrite powders with the powder of barium titanate in isopropanol as the milling medium and in the planetary ball mill for 24h. The obtained powders were then pressed and sintered at different temperatures. The sintering process was optimized and the particular sintering temperatures of each composite within the temperature interval of 1120-1200 °C were determined in order to obtain ceramic samples with high density. The characterization of the obtained ceramic composites was performed by different physical-chemical analytical methods. The X-ray diffraction method was used for monitoring the phase composition of obtained powders and ceramics and based on XRD patterns the optimal sintering temperatures were determined. The morphologie of the powders of pure nickel zinc ferrite and barium titanate powders were analyzed based on the analyses of the images obtained by scanning electron microscopy. It was determined that the powder of nickel zinc ferrit

Multiferroic composites with formula Ni0.7Zn0.3Fe2O4 - BaTiO3 (x = 0.1, 0.3, 0.5, 0.7, 0.9) were prepared by mixing chemically obtained NZF and BT powders in the planetary mill for 24 h. NiZnFe2O4 (NZF) powder was prepared by auto-combustion method starting from nickel, zinc and iron nitrates. Barium titanate (BT) powder was prepared with the same method. The optimization of sintering process was performed. One series of powders were pressed and sintered at 1170 °C, while the others were sintered at 1120 °C. X-ray measurements confirmed the presence of NZF, BT phases and the traces of barium ferrite phase. The microstructures of the ceramics show (Fig. 1.) the formation of grains with different shape and size. The formation of polygonal (NZF grains), rounded (BT grains) and plate like grains (barium ferrite phase) was noticed. The magnetic analyses showed that in the composites due to existence of ferroelectric phase a dilution effect appears.

U ovoj doktorskoj disertaciji ispitivana su magneto-električna svojstva kompozitnih materijala koji se sastoje od magnetne faze, nikl-cink ferita, i feroelektrične faze, barijum titanata u razlicitim masenim odnosima. Maseni odnosi ovih faza su menjani u cilju dobijanja kompozitnog materijala dobrih magnetnih i električnih svojstava. Prahovi čistih polaznih materijala, nikl ferita i barijum titanata sintetisani su hemijskom metodom auto–sagorevanja. Ova metoda predstavlja važnu tehniku za sintezu kompozita, legura, katalizatora, itd. Danas metoda auto-sagorevanja čini veoma popularan pristup za pripremu nanomaterijala koji su našli industrijsku primenu u mnogim zemljama. Prahovi nikl ferita i nikl cink ferita su dobijeni kalcinacijom prekursora na temperaturi od 1000 °C tokom 1h dok je kalcinacija barijum titanata vršena na od 900 °C tokom 2h. Prahovi kompozita dobijeni su homogenizacijom prahova nikl ferita, nikl cink ferita sa prahom barijum titanata u izopropanolu kao medijumu za mlevenje i u planetarnom mlinu u trajanju od 24 h. Dobijeni prahovi su presovani i sinterovani na različitim temperaturama. Izvršena je optimizacija procesa sinterovanja kojom su određene temperature sinterovanja svakog kompozita pojedinačno u intervalu od 1120-1200 °C u cilju dobijanja najveće gustine keramičkih uzoraka. Karakterizacija dobijenih keramičkih kompozita vršena je različitim fizičko hemijskim metodama analize. Metodom rendgenske difrakcije praćen je fazni sastav dobijenih prahova i keramike i na osnovu XRD dijagrama određene su optimalne temperature sinterovanja. Morfologije čestica praha čistog nikl cink ferita i barijum titanata određene su na osnovu analize mikrofotografija dobijenih skenirajućom elektronskom mikroskopijom. Analizom je utvrđeno da se prah nikl cink ferita sastoji od individualnih čestica sfernog oblika, koje su malih veličina ( lt 200 nm). Čestice praha barijum titanata su veličine oko 100 nm, a njihov oblik čestica je takođe sferan. Analizom SEM mikrogr, In this doctoral dissertation magneto-electric properties of composite materials consisting of magnetic nickel zinc ferrite phase and ferroelectric barium titanate phase in different mass ratios were investigated. Mass ratios of these phases were differed in order to obtain composite materials with optimal magnetic and electrical properties. Powders of pure starting materials, nickel zinc ferrite and barium titanate were synthesized by the chemical auto-combustion method. This is important technique for the synthesis of composites, alloys, catalyst, etc. In the present time the auto-combustion method is becoming rather popular method for the preparation of nano materials with industrial application in many countries. Powders of nickel ferrite and nickel zinc ferrite were obtained by the calcination of precursors at the temperatures of 1000 °C with duration of 1h, while the calcination of barium titanate was conducted at 900 °C for 24h. Powders of composites were obtained by homogenization of nickel ferrite and nickel zinc ferrite powders with the powder of barium titanate in isopropanol as the milling medium and in the planetary ball mill for 24h. The obtained powders were then pressed and sintered at different temperatures. The sintering process was optimized and the particular sintering temperatures of each composite within the temperature interval of 1120-1200 °C were determined in order to obtain ceramic samples with high density. The characterization of the obtained ceramic composites was performed by different physical-chemical analytical methods. The X-ray diffraction method was used for monitoring the phase composition of obtained powders and ceramics and based on XRD patterns the optimal sintering temperatures were determined. The morphologie of the powders of pure nickel zinc ferrite and barium titanate powders were analyzed based on the analyses of the images obtained by scanning electron microscopy. It was determined that the powder of nickel zinc ferrit

The aim of this paper is to assess the pozzolanic reactivity of sugar cane straw ash (SCSA) obtained through an auto-combustion process and the mechanical properties of SCSA-containing systems. Characterization of SCSA (X-ray diffraction, chemical composition, particle size, and microscopy) and reactivity studies on hydrated lime/SCSA and Portland cement/SCSA pastes through infrared spectroscopy, thermogravimetric analysis, and microscopy demonstrated the high pozzolanic activity. This reactivity made it possible to achieve good mechanical properties in mortars in which 15 30% of the cement was replaced by SCSA. After 90 days of curing, the SCSA fixed 100% of the lime present in lime/SCSA pastes, and the compressive strength of mortars containing SCSA reached 44 MPa, a value similar to those found for control mortars after the same number of curing days. The results for the microstructural and mechanical properties showed that SCSA is a good pozzolanic material.

The aim of this paper is to assess the pozzolanic reactivity of sugar cane straw ash (SCSA) obtained through an auto-combustion process and the mechanical properties of SCSA-containing systems. Characterization of SCSA (X-ray diffraction, chemical composition, particle size, and microscopy) and reactivity studies on hydrated lime/SCSA and Portland cement/SCSA pastes through infrared spectroscopy, thermogravimetric analysis, and microscopy demonstrated the high pozzolanic activity. This reactivity made it possible to achieve good mechanical properties in mortars in which 15 30% of the cement was replaced by SCSA. After 90 days of curing, the SCSA fixed 100% of the lime present in lime/SCSA pastes, and the compressive strength of mortars containing SCSA reached 44 MPa, a value similar to those found for control mortars after the same number of curing days. The results for the microstructural and mechanical properties showed that SCSA is a good pozzolanic material.

Bismuth ferrite (BiFeO3) is one of the very few materials possessing ordered both electrical dipoles and magnetic moments in very wide range of temperatures. That gives it tremendous opportunities for research and application. BiFeO3 precursor powders were prepared by auto-combustion and soft chemical synthesis methods using different organic compounds as fuels and complexing agents. They were calcined at 600 °C for 2 h, grinded, pressed and sintered at 800 °C for 1 h with quenching. XRD and SEM confirmed formation of very pure BiFeO3 perovskite phase, but problem with low density, which is characteristic for BiFeO3 ceramics, still remained. It doesn’t affect magnetic properties, but has strong influence on electrical and, through them, on multiferroic properties. To define actual, intrinsic properties of material, it is very important to obtain ceramics with densities close to theoretical. For this reason, many treatments were tried in order to raise samples’ densities: powder milling and homogenization, ultrasound, different pressures, various thermal treatments. Powders and ceramic samples were then characterized (particle size analysis, XRD, SEM). The densities of sintered BiFeO3 samples were measured. All the treatments had impact on ceramics density, but some also introduced secondary phases.

Bismuth ferrite (BiFeO3) exhibits ferroelectric and antiferromagnetic properties up to very high temperatures, and is, consequently, considered one of the most promising single phase multiferroic materials. Doping with Y3+ was tested in terms of improving electrical and magnetic properties. Bi1-xYxFeO3 was synthesized by auto-combustion method using urea as a fuel. Precursor powders were annealed, pressed and sintered. Powders and ceramic samples were characterized by XRD, SEM, Raman, electrical and magnetic measurements. X-ray diffractograms and Raman spectra showed transition from rhombohedral to orthorhombic structure at 10 % Y3+ content. SEM images indicated reduction in grain size with higher concentration of Y3+.

NiFe2O4 (NF) and Ni0.5Zn0.5Fe2O4 (NZF) powders as a part of multiferroic composites were prepared by auto-combustion method starting from nickel, zinc and iron nitrates. After the process of self-ignition, fine precursor powders were thermally treated at 1000 oC for 1h forming the nickel ferrite and nickel-zinc ferrite powders [1]. XRD analysis proved the formation of well crystallized cubic spinel structure in both ferrites. Particle size distribution measurements showed the existence of agglomerates. SEM micrographs showed the existence of polygonal grains ~ 100-500 nm. The results of powders characterization are presented in the table I. Ceramics materials were obtained by sintering at 1250 oC for 4 h in the tube furnace. XRD analysis showed the formation of well crystalline spinel structure in both materials. Magnetic measurements of ferrites were carried out and presented in Figure 1. Saturation magnetization moment of NF was lower than for NZF and the fields at which saturation occur was almost the same for both ceramics. The coercivity HC (Oe) was higher for the NZF indicating that it is “softer” than NF [2]. Permeability vs. frequency measurements showed that NZF possesses much higher permeability that NF. On the other hand, the NF permeability value keeps constant values in a broader frequency range than NZF ceramics.

In this study we have prepared nickel ferrite (NF) and nickel zinc ferrite (NZF) nanoparticles by auto-combustion method starting from nickel, zinc and iron nitrates. After the process of self-ignition, fine precursor powder was thermally treated at 1000 °C for 1 h, forming nickel zinc ferrite powders, with molar ratio of Zn 0, 0.3, 0.5, 0.7. XRD characterization showed the formation of well crystallized nickel ferrite and nickel zinc ferrite inverse spinel structure without presence of secondary phases. Ceramic materials were obtained by uniaxial pressing at 196 MPa and sintering at 1250 °C for 4 h in the tube furnace. SEM images at the free surface showed that substitution of Ni2+ ions with Zn2+ ions results in larger grains and lower porosity, confirmed by density measurements. Magnetization results showed ferromagnetic behavior of the NF and NZF materials. Magnetic measurements of ferrites were carried out and presented in Fig. 1. Saturation magnetization moment of NF was lower than for N0.7Z0.3F and N0.5Z0.5F, but slightly higher than for N0.3Z0.7F. With increasing the ratio of Zn to 0.3, magnetization increases, because the Fe3+ ions in the octahedral site interact with other Fe3+ ions. The fields at which saturation occur was almost the same for all materials.

Bismuth ferrite is one of the most promising single multiferroic materials. It exhibits ferroelectric and antiferromagnetic behavior in wide range of temperatures. Many new applications arise due to possibility of magnetization reorientation by electric field and polarization reorientation by magnetic field [1]. Main problem in usage of BiFeO3 is difficulty of obtaining pure phase ceramic and high conductivity as a result of Fe non-stoichiometry. BiFeO3 (BFO) powders were prepared by auto-combustion and soft chemical methods starting from iron and bismuth nitrates. After the synthesis, fine precursor powders were thermally treated for various periods at different temperatures and heating rates. In case of auto-combustion synthesis, several fuels (citric acid, sucrose and urea) and fuel to oxidizer ratios (F/O) were examined, while for soft chemical synthesis two complexing agents were tested: citric and tartaric acids. Low temperature synthesis was also tested without any complexing agent. XRD measurements showed presence of Bi2O3, Bi2Fe4O9 and Bi25FeO39 secondary phases in all powders, and pure perovskite BFO phase for several sintered samples. Powders and ceramics were characterized by SEM/EDS, TG/DTA, particle size distribution and BET surface area measurements. Impedance and magnetic measurements were performed in order to define electrical and magnetic properties of BFO ceramics.

Nanopartículas de cromita y ferrita de cobalto fueron sintetizadas exitosamente mediante el método de auto-combustión. Las propiedades estructurales y magnéticas fueron especialmente estudiadas. Los polvos obtenidos fueron caracterizados mediante Difracción de Rayos-X (DRX), Microscopia Electrónica de Transmisión (MET), medidas de área superficial específica y medidas magnéticas en función de la temperatura y del campo magnético aplicado. Ambos nanocompuestos cristalizaron en la estructura cúbica espinela. El tamaño de las partículas es de, aproximadamente, 30 nm para el CoCr2O4 y 5 nm para el CoFe2O4. Se logró determinar que la cromita y la ferrita de cobalto tienen un área superficial específica de 18,3 m2/g y 38,5 m2/g, respectivamente. La característica principal de las curvas de magnetización en función de la temperatura para el CoCr2O4 es la presencia de una transición magnética aproximadamente a 98K, además de una anomalía, alrededor de 30K. El ordenamiento magnético existente por debajo de 98K se considera que está formado por dos contribuciones: una componente ferrimagnética colineal y una componente en espiral. La ferrita de cobalto presenta una fase ordenada ferrimagnética en todo el rango de temperaturas por debajo de la temperatura ambiente.

Microwave assisted combustion method was used to synthesize nanocrystalline ZnxNi1-xFe2O4 from a stoichiometric mixture of corresponding metal nitrates and urea powders. The structural, chemical and magnetic properties of Ni-Zn ferrite was determined by X-ray powder diffraction (XRD), transmission electron microscopy (TEM), infrared spectroscopy (FTIR), vibrating sample magnetometry (VSM) and DC conductivity measurements. Results showed that the material was spinel structure with a high purity with an estimated crystallite size of similar to 20 nm by X-ray line profile fitting. TEM analysis showed necked near-spherical particles with an average size of similar to 20 nm, reflecting highly crystalline nature of these nanoparticles. Magnetic properties showed anomalities as the Zn doping level increased. This has been explained and attributed to the relative positions of Ni, Zn, and Fe ions in the crystal lattice., QC 20100525