Citrate Gel Research Articles

Study of structural, optical, photocatalytic, electromagnetic, and biological properties Co0.75Mg0.25CexFe2−xO4 of Mg-Co nano ferrites

Nano spinel ferrites with formula Co0.75Mg0.25CexFe2−xO4 (0 ≤ x ≤ 0.25 by step 0.05) were synthesized by using citrate gel auto combustion method and studied their structural characterization, optical studies, photocatalytic, biological and electromagnetic properties. Structural properties carried out by XRD, SEM, EDS, FTIR spectroscopy. The XRD studies confirm the crystalline size & lattice constant of Ce co-doped Co-Mg mixed nano ferrites. Morphology of the samples were examined by SEM and EDS analysis confirmed the proposed sample composition. FTIR spectral analysis help to confirm the formation of spinel structure in ferrite samples. Further optical studies confirm the band gap energy and cut off wavelength. Photocatalytic degradation of MB and AR dyes were carried out and good results were observed the degradation activity due to the catalyst heat treatment. Antibacterial studies confirmed that the nanoparticles are toxic to Bacillus subtilis, staphylococcus aureus (gram-positive strains) and Escherichia coli, Klebsiella pneumonia (gram-negative strains) Bacillus subtilis showed highest zone of inhibition of 13.3 mm. Saturation magnetization, coercivity, and remanence magnetization were calculated by VSM and Co0.75Mg0.25Ce0.25Fe1.75O4 was found to have high saturation magnetization that indicates that the sample behaves like a super para magnet. The Squareness of Co-Mg-Ce mixed nano ferrites initially decreases than increases hence the system changes from soft ferrites to hard ferrites. The electromagnetic properties such as AC conductivity (σAC), Dielectric constant (ε/), and impedance analysis are reported. The cole–cole plots shows the single semicircle behaviour.

Effect of Ni2+ substitution on structural, magnetic and electrical traits of Ba1-xNixFe2O4

Nickel substituted Barium ferrites is synthesized by citrate gel method. Nickel which is transition metal used to tailor the properties of the Ba spinel ferrites. The characterization techniques such as thermogravimetry–differential thermal analysis (TG-DTA), X-ray diffraction (XRD), vibrating sample magnetometry (VSM), Fourier transform infrared spectroscopy (FTIR), ultra-violet diffuse-reflectance spectroscopy (UV-DRS), scanning electron microscopy-energy dispersive X-ray spectroscopy (SEM-EDX), transmission electron microscopy (TEM), Raman analysis and direct current (DC) electrical conductivity are used to investigate various properties. XRD and rietveld refinement confirmed the existence of orthorhombic as well as cubic phase with the decrease in lattice parameters in orthorhombic phase. FTIR spectra confirmed the presence of absorption bands for tetrahedral and octahedral sites. Tauc’s plots accredited the increase in band gap with increase in Ni content. The magnetic hysterisis loop exhibited large variation in coercivity and remanence. Increased Yafet-Kittel (Y-K) angle indicated redistribution of ions amongst the sites strenthening the A-B exchange interactions. DC electrical conductivity observed the conductive switching from n-type to p-type. Thermally activated charge carriers and hopping of electrons boost drift mobility. The activation energy of conduction is observed in the range of 0.40 to 0.85 eV. Raman peaks confirmed formation of orthorhombic as well as cubic phase.

Magnetically separable mixed metal oxide nanocomposite (Pd/MnFe2O4) for Suzuki cross-coupling in aqueous medium

Magnetically separable Pd/MnFe2O4 nanocomposite has been synthesized by coupling palladium with MnFe2O4via citrate gel auto combustion and deposition precipitation method. The physicochemical and microscopic study of Pd/MnFe2O4 was investigated using various characterization techniques. The zeta potential of the prepared nanocomposite Pd/MnFe2O4 was found to be highly negative value of -36.7 mV, which stabilizes the particle in its dispersed state and also helps to polarize the aryl-halide bond. The catalytic activity of Pd/MnFe2O4 was explored for Suzuki cross-coupling of aryl boronic acids and aryl halides (I, Cl, Br) in an aqueous medium. Interestingly, the rate of the slow oxidative addition step of the reaction is enhanced due to the high negative surface charge of the catalyst. It is worth mentioning that high turnover number (TON) and turnover frequency (TOF), thermal stability, ease of handling, nontoxic, magnetically separable, and recyclable are the remarkable properties of the present catalyst. Moreover, the protocol was found to be significant with respect to reaction time, substrate scope, the yield of products, and solvent used for the reaction.

Colossal dielectric response and complex impedance analysis of LaFeO3 ceramics

The present investigations mainly focused on the colossal dielectric response and complex impedance analysis of LaFeO3 ceramics. The studied sample was prepared by a citrate gel method. Structural and microstructural properties are analyzed from the XRD pattern and SEM micrograph. The anomalies in the dielectric constant versus temperature plots are analyzed on the basis of polarization induced by the Maxwell-Wagner mechanisms and ferromagnetic interaction between the Fe[Formula: see text] ions driven by the oxygen vacancy mediated Fe[Formula: see text]–V[Formula: see text] –Fe[Formula: see text] exchange interaction A giant dielectric permittivity in the order of [Formula: see text]105 was observed in the sample even at the room temperature for 100 Hz. The colossal dielectric constant in LaFeO3 is mainly driven by the internal barrier layer capacitor (IBLC) formation. The formation of IBLC was explained on the basis of highly insulating grain boundary and less resistive/semiconducting grain, which was confirmed from both the resistance and capacitance of grain and grain boundary from the impedance analysis. The non-Debye-type relaxation process associated with the grain and grain boundary effect was investigated from the broad and asymmetric relaxation peak. The relaxation time for both the grain and grain boundary effect was also calculated. In addition to this, we have also analyzed the normalized bode plot of imaginary part of impedance and electrical modulus which suggests the relaxation process dominated by the short-range movement of charge carriers.

Comparison between the effect of different medical drugs used to improve endometrial receptivity in patients with thin poorly vascularized endometrium

Background: Pregnancy has been one of life’s great mysteries. The endometrium is where life begins, and a receptive endometrium lies at the crossroads of menstruation and pregnancy. Aim of the study: To evaluate the effects of different medical drugs used routinely to improve endometrial thickness, vascularity, and pregnancy rates and to find out the best medical protocol could be used to improve endometrial thickness, vasculature, and pregnancy rate for patient with thin and poorly vascularized endometrium regardless the cause. Materials and methods: The study was carried out on 200 infertile women who have thin , poorly vascularized endometrium, after they matched the inclusion and exclusion criteria , those patients were divided randomly into five groups ; 40 patient in each group, group A received esterofem oral 2mg tablet every 12 hours from day 2 of menstrual cycle till the day of ovulation trigger , group B received vagifem vaginal tablets 25 microgram from the fourth day of menstrual cycle for 15 days or till the day of ovulation trigger, group C received sildenafil citrate gel 3 gm which containing 37.5 mg sildenafil every 12 hours from the 2nd day of menstruation till the day of ovulation trigger.

Effect of Ni2+ substitution on magnetic, optical and electrical properties of SrFe2O4

Citrate gel combustion method is used for the synthesis of Ni2+ substituted strontium ferrite Sr1-xNixFe2O4 (x = 0.0, 0.2, 0.4, 0.6, 0.8). The characterization of synthesized material is done by different techniques. Fourier transform Infra-red (FT-IR) spectra revealed the inverse spinel structure and showed slight shift in spectrum. X-ray diffraction (XRD) patterns demonstrated the orthorhombic phase of spinel formation with trace of secondary phase impurity of SrCO3. Scanning electron microscopy (SEM) images showed agglomeration of particles. The effect of Ni2+ substitution in SrFe2O4 on structural, magnetic, optical and direct current (DC) electrical resistivity properties are investigated. Room temperature vibrating sample magnetometer (VSM) studies indicated increase in trend of saturation magnetization (Ms) and remanence magnetization (Mr) with increase in content of Ni2+ ion. The squareness ratio (SQR) Mr/Ms for SrFe2O4 is found to be 0.5752, while for remaining samples it is found to be less than 0.5 which demonstrated multi domain to single domain transition. Variation of band gap energy with Ni2+ substitution is reported with the help of ultra-violet diffuse reflectance spectra (UV-DRS). Temperature dependent DC electrical resistivity by two probe method measurement obeyed Arrhenius equation and revealed the typical semiconducting behavior of the samples. The change in slope of line observed in resistivity due to ferrimagnetic to paramagnetic transition in all samples attributed strong exchange interaction between the outer and inner electrons. Activation energy (Ea) for ferri and paramagnetic region is calculated. For ferrimagnetic region the Ea is found to increase with increasing Ni2+ content while, in paramagnetic region for Ni2+ substituted samples the Ea is found to be greater than 0.2 eV which inferred the hopping motion of small polarons are responsible for conductivity. The complex impedance spectra revealed the information about conduction mechanism.

Production of AB5 materials from spent Ni-MH batteries with further tests of hydrogen storage suitability

A novel approach for the reuse of rare earth (REE) elements generated during hydrometallurgical processing of Ni-MH batteries as alternative sources is provided to valorize Ni-MH batteries wastes. The production of AB5-based alloys from spent Ni-MH waste was thoroughly investigated. The REE elements were recovered as a mixture in oxalate form and annealed at 900 °C to obtain a single-phase REEs oxide REE2O3. Citrate gel and glycine nitrate processes followed by the Ca reduction process under H2 atmosphere were used to produce the AB5 alloys. The alloys were successfully produced, and their crystal structure and morphology have been studied using X-ray diffraction (XRD), scanning electron microscopy (SEM) with supporting energy-dispersive X-ray (EDS) analysis. Nanoparticles with a size of 173±3 nm and 150±8 nm were observed using transmission electron microscopy (TEM) for CG and GNP alloys. Studied samples were subjected to hydrogenation, and the structural changes were depicted.

Effect of B site substitution in Gd2B2-xNiyO7-δ (B= Ti, Zr) ternary metal oxide catalysts in dry reforming of methane

Structured catalysts are emerging as active and durable catalysts in dry reforming of methane due to their inherent characteristics like lattice insertion of active metals and consequent stability imparted. Here we report Ti and Zr substituted Gd2B2-xNiyO7-δ (B = Ti, Zr) catalysts synthesized by citrate gel method, which are characterized and tested for dry reforming of methane. Structure and Ni substitution has been confirmed by Rietveld refinement of powder XRD patterns and Raman analysis. TPR and CO2-TPD were performed to analyze the reducibility and effect of basic sites of catalysts in DRM activity. Ni doped Ti analogue shows stable and superior activity towards dry reforming of methane for 100 h. The in situ IR studies and XPS analysis confirmed the presence of surface hydroxyl species in this catalyst, which triggers the activation of CO2 and provides higher and durable activity in dry reforming reaction. Absence of any C formation in this catalyst after durability test indicates the mechanism of C gasification by the surface hydroxyl species enhancing stable activity for long durations.

Synthesis, structural, photocatalytic and anti-cancer activity of Zn doped Ni nano chromites by citrate gel auto combustion method

Nano structured zinc doped nickel chromites Ni1-xZnxCr2O4 (where 0 ≤ x ≤ 1 by step 0.2) were fabricated by the citrate gel auto combustion route and were characterized with several techniques like XRD, SEM, EDS, Transmission Electron Microscope (TEM), FT-IR, UV–Vis and Photoluminescence. A formation of single-phase cubic structure and the crystalline state of fabricated samples in size range of 9-to–20 nm were established by the X-ray diffraction studies. The SEM images have revealed the shape of Ni substituted Zn nano chromite. The existence of Ni, Zn, Cr and O in the series of samples were also confirmed by the elemental analysis (EDS) study. FTIR spectra revealed the formation of metal oxide bands and spinel chromite structures which have tetrahedral and octahedral stretching frequency bands. Using the UV–Vis spectrometer, the optical properties of Ni-Zn chromite has been studied and also have that the band gap energy of Ni chromite (3.54 eV) is smaller than that of Zn chromite (3.85 eV). The optical band gap energies were found to be 2.10–3.08 eV for the direct band gap calculated from Tauc plots. The present study mainly focused on the photo-degradation of methylene blue and acid red on the Ni-Zn chromite’s under UV light. The chromites have shown good and clear degradation at certain time intervals with the reference. The biological activity of the synthesized Ni-Zn chromites were performed for their anticancer activity on Hela cell lines and all the molecules exhibited with different IC50 values ranging from 21.83 to 74.15.

Impact of Sintering Temperature on the Electrical Properties of La0.9Sr0.1MnO3 Manganite

La0.9Sr0.1MnO3 nanoparticles were prepared using the citrate–gel route and sintered at different temperatures (TS = 600 °C, 800 °C, and 1000 °C). The x-day diffraction patterns reveal that the samples exhibit a single phase with a rhombohedral (R3¯C) structure. The transmission electron microscopy technique shows an increase in the grain size when the sintering temperature (TS) rises. The obtained values are approximately similar to that of crystallite size calculated from x-ray diffraction patterns. The impact of sintering temperature (TS) on the electrical properties of La0.9Sr0.1MnO3manganite is examined using the impedance spectroscopy technique. A metal-semi-conductor transition at a specific temperature (TM-SC) is observed for all samples. Indeed, the sintering temperature increase induces the shift of this transition temperature toward higher temperatures. Such a behavior is explained by the increase in the grain size. An agreement between the metal-semi-conductor transition values coming from the DC resistivity and the grain boundaries analyses is observed. This agreement proves the contribution of the grain boundaries in the electrical properties of the studied samples. In addition, the presence of the relaxation phenomenon is confirmed. The fitted Nyquist plots show the correlation between the microstructure of the material and the electrical properties using an electrical equivalent circuit model. The DC resistivity and the impedance analyses reveal the thermal activation of the transport properties in the investigated system.

Effect of chromium substitution on the electrical and magnetic properties of multiferroic yttrium manganite

Yttrium Manganite is a multiferroic material and has potential applications in Ferroelectric Random Access Memories. Chromium is substituted with a view to enhancing the electrical conductivity. Compositions belonging to the series Y1−xCrxMnO3, (x = 0, 0.05, 0.1, and 0.3) were synthesized by employing a citrate gel method. Pre characterized samples using X-ray diffraction and Scanning Electron Microscopy were then subjected to impedance spectroscopy to understand the conduction mechanism vis-à-vis small polaron hopping or variable range hopping. Cole-Cole and Nyquist plots were utilized to arrive at the equivalent circuit. Ferroelectric measurements were carried out to understand the polarization mechanisms. Magnetic measurements were also conducted to observe the change in magnetic properties with Chromium substitution. Field Cooled (FC) and Zero Field Cooled (ZFC) magnetization measurements revealed the presence of ferromagnetic clusters in an antiferromagnetic matrix. It has been found that Chromium substitution enhances the electrical conductivity while it diminishes the ferroelectric properties.

Preparation of highly dispersed CuO-ZnO-ZrO2 catalysts and their improved catalytic performance for hydrogenation of CO2

Highly dispersed CuO-ZnO-ZrO2 (CZZ) catalysts were prepared by the citrate gel method. The structures of catalysts and precursors were characterized by XPS, BET, XRD, H2-TPR, H2-TPD, CO2-TPD, and TG-DTA. The effects of wet gel drying time and citric acid dosage on the catalyst structure were studied and compared with the catalysts prepared by the combustion method to investigate the performance of different catalysts for CO2 hydrogenation to methanol. Studies have shown that prolonging the drying time of wet gel can effectively prevent the splashing of the catalyst during calcination. The BET surface area of the catalyst dried at 120 °C for 48 h is 44.8 m2/g, which is higher than that of the combustion method. When the amount of citric acid is equal to the stoichiometric ratio, the catalyst has the best performance. Under the conditions of 240 °C, 2.6 MPa, space velocity of 3600 h–1, and H2/CO2 volume ratio of 3, the space–time yield of methanol reaches 110.3 g/(kg h). Excessive citric acid will affect the dispersion of catalyst components and result in decomposition residue covering catalyst surface active sites, which is not conducive to CO2 hydrogenation reaction.

Investigation of structural and dielectric properties of Gd3+ substituted nickel-zinc ferrite prepared via low-temperature citrate gel self-ignited process

The productive of nanocrystalline Gd3+ substituted mixed Ni0.7Zn0.3GdxFe2-xO4 (where × = 0.000, 0.005, 0.010, 0.015, 0.020 and 0.025) spinel ferric material was synthesized using the low-temperature citrate assisted self-ignited process. The structure, microstructure, and elemental investigation were examined by XRD, SEM, EDX and TEM investigation. It revealed that the prepared accumulation a spinel system with an fd-3m space group. Scanning electron microscopy has shown the agglomeration of irregular morphology of nickel-zinc ferrite sample, EDX also confirms the presence of desired elements. TEM micrographs support the XRD data and the average particle size was estimated (approximately below 50 nm). The dielectric investigation is executed by using complex impedance spectroscopy in the frequencies 20 Hz to 2MH. Dielectric properties such as real (ε'), imaginary (ε'') parts in addition loss tangent (tan δ) decreased by means of rising frequency for prepared ferric materials. The investigation of complex impedance outcomes showed “the capacitive and reactive characteristics”. A study of the modulus electric evaluation suggested that relaxation processes in this nickel-zinc with Gd3+ substituted compositions are of a “non-Debye’s type”. Replacing Fe ions through Gd3+ ions significantly impacts synthesised nano ferrites' electrical properties.

Uncovering the consequences of Ag1+ on nano-structural, magneto-optical, antibacterial, and antifungal response of nickel oxide particles

Metal oxide nanoparticles existing in transition metal series have intensely earned high research interest among material scientists by virtue of their dispersive magnetic nature desirable for antimicrobial action. Herein, we report the unsubstituted and silver (Ag) doped nickel oxide nanoparticles with varying dopant concentrations AgxNi1−xO (x = 0.00, 0.05, 0.10, and 0.15 M) prepared via flexible sol–gel citrate route at optimum temperature. The well-resolved prominent peaks from X-ray Diffraction (XRD) pattern confirmed the micro-structural attributes of NiO particles and the corresponding crystallite size decreases from 25.67 to 10.93 nm (nm) upon doping. The bandgap energy evaluated from the Tauc plot traced an increasing trend from 2.48 to 3.09 eV affirming the blue shift reasoned with the Burstein Moss phenomenon. Scanning Electron Microscopy (SEM) analysis portrayed the formation of spherical nanoparticles and the particle size was calculated. The phase purity and the chemical composition of nanoparticles were elucidated from Energy Dispersive X-ray (EDX) spectra which endorse only the presence of Ni, Ag, and O metals. Fourier Transform Infra-Red (FTIR) spectroscopy analysis operated in an IR vibrational spectral span confirms the functional group matrix. Dielectric constant and loss of doped nanoparticles were discussed where the loss decreases with increasing dopant concentration. Saturation magnetization (Ms) and coercivity (Hc) were calculated from Vibrating Sample Magnetometer (VSM) studies where Ms perform a declining tendency from 39.96 to 2.86 emu/g which is favorable in the construction of antennas and memory storage equipment. In addition, the nanoparticles were tested against different bacterial and fungal organisms to examine their antimicrobial activity wherein the high concentration (Ag0.15Ni0.85O) doped nanoparticles exhibited a higher antimicrobial response.

Study of photo catalytical, antimicrobial activity, dielectric and ac impedance properties of Zn doped Mg nanoferrites synthesized from citrate gel auto combustion method

Mg–Zn nano ferrites with composition Mg(1-x)ZnxFe2O4 where x = 0.0 to 1.0 with 0.2 variation, were fabricated through citrate gel auto combustion method with step wise variation 0.2 mol%. UV–Visible spectroscopy confirmed the direct allowed transitions and optical band gap increased from 2.61ev to 2.71 with the addition of dopant Zn. The PL spectroscopy revealed that the broad near band edge emission in visible range 350–450 nm wavelength region. Antibacterial efficiency of the nano ferrites enhanced with the antibacterial dopant element Zn against gram positive Bacillus subtilis (MTCC 121) and gram negative Escherichia coli (MTCC 1687) strains. Organic dyes such as methylene blue and acid red were used to do photocatalytical degradation process and significant rate of degradation was found. Frequency dependent AC conductivity (σac) of the nano ferrites increased as a function of temperature and dopant Zn content. Dielectric parameters such as dielectric constant, dielectric loss (tan δ) were decreased with applied frequency. The results of dielectric studies reveals that the dielectric dispersion because of the hopping mechanism of electrons takes place in between Fe2+ and Fe3+ ions.

Synthesis of Ni-Zn-Mg-Zr spinel ferrites as high-performance electromagnetic wave absorber in Ku band

The present work deals with the magnetic characterization and microwave absorption characterization of magnesium and zirconium co-substituted nickel-zinc spinel ferrites (Ni0.6Zn0.4(MgZr)xFe2-2xO4; x = 0.05, 0.10, 0.15 and 0.20) synthesized through sol–gel citrate precursor method. The magnetic properties have been analysed using vibrating sample magnetometer (VSM) and the complex electromagnetic properties have been determined with the help of vector network analyser (VNA) in Ku band i.e., 12.4–18 GHz. The electromagnetic wave absorption analysis has been done by monitoring change in reflection loss (RL) values with increasing frequency and thickness of the samples. The minimum RL equal to −33.4 dB has been obtained for composition with x = 0.15 at a matching frequency of 17.21 GHz and matching thickness of 1.6 mm.

Citrate gel synthesis of vanadium diboride

Toward synthesizing vanadium diboride (VB2), mainly mechanochemical and carbothermic routes have been hitherto administired as well as combustion, self-propagating high temperature synthesis (SHS), and solid state metathesismethods. However, methods suggested to date do not deliberately deal with the oxidation state of the vanadium forming the oxide, formation conditions and morphology. Additionally, studies usually suggest an ultimate single reaction, disregarding side reactions. This narrow thermodynamic approach lacks key information in regards to the required conditions. Herein, this study reports the laboratory scale synthesis of VB2 nanopowders employing citrate gel method. The process is carried out using ammonium metavanadate (NH4VO3) as the vanadium source, boric acid (H3BO3) as the boron source, and citric acid (C6H8O7) as a chelating agent. Raw powder chelate is subjected to boro/carbothermic reactions under argon atmosphere in the range of 1100–1500 °C correlated with thermodynamic calculations with a 100 °C interval which are in good agreement with the experimental data. The resulting material is characterized to be at least 92% VB2 within the possibility of excessive graphitic carbon, carbon deficient vanadium carbide (V8C7) and/or non-stoichiometric VxBy(yx≤32) remaining as impurities. The formation mechanisms referring Liquid-Solid (LS) and Vapour-Solid (VS) reaction pathways throughout the major steps are described.

The crystal chemistry and electrical properties of Fe doped Ca12Al14O33 (Mayenite)


 
 
 X-ray and neutron powder diffraction have been used to study the crystal chemistry of Fe doped mayenite (Ca12Al14-xFexO33). Solid- state synthesis was used to prepare Ca12Al14-xFexO33 where x = 0, 0.1, 0.2, 0.5 and 0.6 and the citrate gel route was used to prepare Ca12Al14-xFexO33 where x = 0, 0.05, 0.1, 0.2, 0.3 and 0.4. X-ray powder diffraction data indicate that samples with the same composition but synthesized by the citrate gel route were more likely to be phase pure than samples obtained by traditional solid-state synthesis. The refined lattice parameters were observed to increase with increasing Fe concentration, irrespective of the synthesis method. Refined neutron powder data confirm that Fe is going into Al site rather than Ca site. A 2-point probe was used to measure the electrical properties of the Fe doped citrate gel synthesized samples and showed that the resistivity increases for the Fe doped samples compared to the undoped mayenite.
 
 

Comparison of microwave absorption characteristics of Co-Zr substituted Ni-Zn ferrites and Mg-Zr substituted Ni-Zn ferrites in Ka band (26.5 – 40 GHz)

In the present work, microwave absorption characteristics of cobalt-zirconium (Co-Zr) doped and magnesium-zirconium (Mg-Zr) doped nickel zinc (Ni-Zn) ferrites in Ka band, have been compared. The samples with chemical composition, Ni0.6Zn0.4(CoZr)xFe2-2xO4 (x = 0.05, 0.10, 0.15, 0.20 and 0.25) and Ni0.6Zn0.4(MgZr)xFe2-2xO4 (x = 0.05, 0.10, 0.15 and 0.20) have been prepared by sol–gel citrate precursor route and then, sintered at 1000 °C. The absorption characterization has been done by using vector network analyser (VNA) for both the series. Enhancement of dielectric and magnetic properties is observed with the addition of Co-Zr & Mg-Zr in simple Ni-Zn spinel ferrites, which make these ferrites suitable to work as microwave absorber materials (MAMs) in high frequency shielding applications. The minimum values of reflection loss (RL) obtained in both the series have been compared and it has been found that Mg-Zr substituted Ni-Zn ferrites (with lowest RL equal to −53.19 dB) perform better in terms of absorption than their counterpart Co-Zr doped Ni-Zn ferrites (with lowest RL equal to –33.06 dB). The prepared compositions of both the series, can be effectively used as high-performance microwave absorbers.

Ferroelectric-Ferromagnetic Heterostructures based on Sodium Substituted Lanthanum Manganite Thin films deposited on PMN-PT substrate by Pulsed Laser Deposition

Phase pure targets of sodium substituted lanthanum manganites (LNMO) were prepared by citrate gel method and characterized. These targets were laser ablated by pulsed laser deposition technique and were deposited simultaneously on silicon and relaxor ferroelectric PMN-PT substrates with a view to fabricating ferroelectric-ferromagnetic 2D heterostructures. Magnetization measurements reveal a higher magnetization for films of 100 nm thickness than the 300 nm thick films. The PMN-PT substrate influences the magnetic properties of sodium substituted lanthanum manganite thin films. The strain effects are higher for 100 nm thin films. The saturated polarization-electric field (P-E) loop measurements carried out on films demonstrated that, there is a considerable change in hysteresis parameters (coercivity and remanent polarization) upon thin film deposition. PMN-PT LNMO thin films can be viewed as a heterostructure where ferromagnetism and ferroelectricity co-exist and has potential applications in magnetoelectrics.