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Effect of dysprosium substitution on structural and dielectric properties of BiFeO_3-PbTiO_3 multiferroic composites

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Journal of Rare Earths 2015年第6期33卷 639-646页

作者： N.k.Mohanty A.k.Behera S.k.satpathy Banarji Behera P.Nayak Materials Research Laboratory School of Physics Sambalpur University

0.5BiDyxFe1-xO3-0.5PbTiOa（0.5BDxF1-x-0.5PT）（x=0.00, 0.05, 0.10, 0.15, 0.20） multiferroic composites were pre- pared by conventional solid state reaction method. Structural characterization was performed by X-ray diffraction and the mate- rials showed tetragonal structure at room temperature. Surface morphology of the composites was studied by a scanning electron microscope （SEM）. Frequency and temperature dependence of dielectric constant （er） and dielectric loss （tan~） of 0.5BDxF1_x- 0.5PT were measured in a wide range of frequency （100 Hz to 1 MHz） and temperature （25 to 400 ~C）. The analysis of the study showed that the er and tang decreased with increasing frequency in the given range for all the samples which could be explained through the occurrence of dipole relaxation process. The effect of substitution of rare earth element dysprosium （Dy） showed increase in er in all the samples prepared for different concentrations from 0.00 to 0.20. An explanation for high value of er for Dy modified 0.5BiFeO3-0.5PbTiO3 （0.5BF-0.5PT） compared to Gd modified 0.5BF-0.5PT was provided. The variation of AC conductivity with inverse temperature found to obey the Arrhenius equation and the composites showed negative temperature coefficient of resistance （NTCR） behavior. The activation energy was found to be in the range from 0.25 to 0.40 eV for all the studied samples.

关键词： X-ray diffraction dielectric constant tangent loss activation energy rare earths

Effect of Rare Earth Doping on Impedance,Modulus and Conductivity Properties of Multiferroic Composites:0.5(BiLa_xFe_(1-x)O_3)–0.5(PbTiO_3)

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Acta Metallurgica Sinica(English Letters) 2015年第7期28卷 847-857页

作者： Ajay kumar Behera N.k.Mohanty S.k.satpathy Banarji Behera P.Nayak Materials Research Laboratory School of PhysicsSambalpur University

The Lanthanum-doped bismuth ferrite–lead titanate compositions of 0.5（Bi LaxFe1-xO3）–0.5（Pb Ti O3）（x = 0.05,0.10,0.15,0.20）（BLxF1-x-PT） were prepared by mixed oxide *** characterization was performed by X-ray diffraction and shows a tetragonal structure at room *** lattice parameter c/a ratio decreases with increasing of La（x = 0.05–0.20） concentration of the *** effect of charge carrier/ion hopping mechanism,conductivity,relaxation process and impedance parameters was studied using an impedance analyzer in a wide frequency range（102–106Hz） at different *** nature of Nyquist plot confirms the presence of bulk effects only,and non-Debye type of relaxation processes occurs in the *** electrical modulus exhibits an important role of the hopping mechanism in the electrical transport process of the *** ac conductivity and dc conductivity of the materials were studied,and the activation energy found to be 0.81,0.77,0.76 and 0.74 e V for all compositions of x = 0.05–0.20 at different temperatures（200–300 ℃）.

关键词： X-ray diffraction Composite materials Impedance spectroscopy Modulus studies Activation energy Relaxation phenomena

Role of hydrazine and hydrogen peroxide in aluminium hydroxide precipitation from sodium aluminate solution

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Transactions of Nonferrous Metals Society of China 2015年第2期25卷 615-621页

作者： N.k.SAHU C.k.SARANGI B.DASH B.C.TRIPATHY B.k.satpathy D.MEYRICk I.N.BHATTACHARYA Academy of Scientific and Innovative Research Institute of Minerals and Materials Technology Council of Scientific and Industrial Research National Aluminium Company Chemical and Mathematical Sciences Murdoch University

Aluminium hydroxide precipitation from synthetic sodium aluminate solution was studied in the presence of hydrazine or hydrogen peroxide. The addition of low concentration of hydrazine is found to be effective, while higher amount of hydrogen peroxide is required to generate similar effect. XRD data confirm the product phase to be gibbsitic by nature. The scanning electron micrographs （SEM） show that agglomerated products form in the presence of hydrazine while fine discrete particles are produced with hydrogen peroxide. The probable mechanism of precipitation in the presence of hydrazine and hydrogen peroxide is also discussed.

关键词： aluminium hydroxide hydrazine hydrogen peroxide sodium aluminate precipitation

Complex impedance properties of LiSr_(2)Nb_(5)O_(15) ceramic

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Journal of Advanced Ceramics 2012年第3期1卷 221-226页

作者： N.k.MOHANTY S.k.satpathy Banarji BEHERA P.NAYAk R.N.P.CHOUDHARY School of Physics Materials Research LaboratorySambalpur UniversityJyoti ViharBurla-768019OdishaIndia Department of Physics ITERS.O.A.UniversityBhubaneswar-751030OdishaIndia

The polycrystalline sample of LiSr2Nb5O15(LSN)was prepared by a high-temperature solid state reaction *** impedance parameters were studied using an impedance analyzer in a wide range of frequencies(102-106 Hz)at different temperatures(28-500℃).Nyquist plot reveals the presence of bulk effect *** bulk resistance of the compound decreases with rise in temperature which shows the negative temperature coefficient of resistance(NTCR)like a *** ac conductivity spectrum was found to obey Jonscher’s universal power *** conductivity(bulk)with temperature demonstrates that the compound exhibits Arrhenius type of electrical conductivity and the activation energy found to be 0.97 eV.

关键词： niobates conductivity complex impedance modulus

kinetics and mechanisms of solvent extraction and separation of La(Ⅲ) and Ni(Ⅱ) with DEHPA in petrofin

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Transactions of Nonferrous Metals Society of China 2019年第7期29卷 1538-1548页

作者： Swagatika satpathy Sujata MISHRA Department of Chemistry Institute of Technical Education and ResearchSiksha ‘O’ Anusandhan Deemed to be University

The kinetics of extractive separation of La(Ⅲ) and Ni(Ⅱ) from nitrate medium in the presence of lactic acid (HLac) using di-2-ethylhexyl phosphoric acid (DEHPA) diluted in petrofin was investigated using a cell with constant interfacial area and continuous stirring. The effects of stirring speed, interfacial area, pH, HLac concentration, extractant concentration, concentrations of metal ions and temperature on the extraction rate were examined. Results suggested that the extraction regime is diffusion-controlled. The reaction which occurred at the interface was found to be the rate-determining step. The extraction rates of both metal ions are found to be independent of pH. The extraction rates of La(Ⅲ) and Ni(Ⅱ) are first-order dependent with respect to lactic acid and metal ions (La(Ⅲ) and Ni(Ⅱ)) concentrations. The extraction rate of La(Ⅲ) is first-order dependent on DEHPA concentration and for Ni(Ⅱ), it varies to the power of 1.5. The separation of La(Ⅲ) and Ni(Ⅱ) from nitrate solution is possible at low interfacial area and low stirring speed.

关键词： extraction separation kinetics mechanism La(Ⅲ) Ni(Ⅱ)

Electric field tuning of the anomalous Hall effect at oxide interfaces

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npj Computational Materials 2019年第1期5卷 619-623页

作者： Sayantika Bhowal Sashi satpathy Department of Physics&Astronomy University of MissouriColumbiaMO 65211USA

Anomalous Hall effect is the phenomenon where the transport properties of the spin-polarized electrons are governed by the spinorbit coupling that couples the orbital and spin degrees of freedom of the *** we show that the anomalous Hall effect at a magnetic interface with strong spin-orbit coupling can be tuned with an external electric *** altering the strength of the inversion symmetry breaking,the electric field changes the Rashba interaction,which in turn modifies the magnitude of the Berry curvature,the central quantity in determining the anomalous Hall *** effect is illustrated with a square lattice model,which yields a quadratic dependence of the anomalous Hall conductivity for small electric *** density-functional calculations were performed for the recently grown iridate interface,viz.,the(SrIrO_(3))1/(SrMnO_(3))1(001)structure,both with and without an electric field,which show a strong electric field *** effect may be potentially useful in spintronics applications.

关键词： field. effect coupling

Electrical conductivity of Gd doped BiFeO3-PbZrO3 composite

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Frontiers of Materials Science 2013年第3期7卷 295-301页

作者： Santosh kumar satpathy Nilaya kumar MOHANTY Ajay kumar BEHERA Banarji BEHERA Pratibindhya NAYAk Materials Research Laboratory School of Physics Sambalpur University Jyoti Vihar Burla-768019 Odisha India

The composite, 0.5（BiGd0.15Fe0.85O3）-0.5（PbZrO3）, was synthesized using the solid-state reaction technique. The formation of the compound was confirmed by XRD with an orthorhombic structure at room temperature. The impedance parameters were studied using an impedance analyzer in a wide range of frequency （10z-106Hz） at different temperatures. The Nyquist plot suggests the contribution of bulk effect and a slight indication of grain boundary effect and the bulk resistance decreases with a rise in temperature. The presence of temperature-dependent relaxation process occurs in the material. Electrical modulus reveals the presence of the hopping mechanism in the materials. The value of exponent n, pre-factor A and adc were obtained by fitting ac conductivity data with Jonscher＇s universal power law. The activation energies calculated from the ac conductivity were found to be 0.50, 0.46, 0.44, 0.43, 0.42 and 0.38 eV at 1, 10, 50, 100, 500 kHz and I MHz respectively in the temperature region of 110℃-350℃. The dc conductivity was found to increase with the rise in temperature. The activation energy calculated from complex impedance plot and from the fitted Jonscher＇s power law are very close, which results similar type of charge carrier exist in conduction mechanism of the material.

关键词： solid state reaction XRD impedance electrical conductivity

Dielectric and frequency-dependent transport properties of lanthanum-doped bismuth ferrite

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Journal of Advanced Dielectrics 2019年第4期9卷 38-46页

作者： A.k.Sahu S.k.satpathy Banarji Behera School of Physics Sambalpur UniversityJyotiVihar Burla 768019OdishaIndia Centurion University of Technology and Management Odisha India

Polycrystalline samples of Bi_(1-x)La_(x)FeO_(3)[x=0.5,0.6,0.7 and 0.8]were synthesized through high temperature solid state reaction *** structural studies of the compounds were done using X-ray diffraction *** constant and dielectric loss were studied for various frequencies(100 Hz–10^(4)Hz)at different *** temperature-dependent non-Debye type relaxation process was suggested in the materials from the analysis of frequency-dependent electrical data at different *** dependence of dc and ac conductivity at various frequencies showed negative temperature coefficient of resistance(NTCR)*** frequency dependence of ac conductivity at different temperatures obeyed Jonscher’s universal power *** temperature dependence of dc and ac conductivity was fitted to Arrhenius *** activation energies at different temperature ranges were calculated to know the charge species involved in the conduction process.

关键词： Solid state reaction XRD impedance electrical conductivity

Modification of structural and dielectric properties of polycrystalline Gd-doped BFO–PZO

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Journal of Advanced Dielectrics 2018年第5期8卷 1-21页

作者： Ambika Ray Banarji Behera Tanmoy Basuy Saumitra Vajandar Santosh kumar satpathy Pratibindhya Nayak Material Research Laboratory School of Physics Sambalpur UniversityJyoti Vihar BurlaOdisha 768019India Centre for Advanced 2D Materials National University of Singapore Singapore 117546Singapore Centre for Ion Beam Applications National University of Singapore Singapore 117542Singapore Department of Physics School of Applied Science Centurion University of Technology and Management BhubaneswarOdisha 752050India

(1-y)(BiFe_(1-x)GdxO_(3))–y(PbZrO3)composites(y=0:5),having four different Gd concentrations(x=0:05,0.1,0.15,and 0.2),were synthesized and their structural,dielectric,and ferroelectric properties have been studied using different characterization *** addition,to investigate the effect of ion implantation on the microstructure and dielectric properties,these composites were exposed to 2 MeV He+-*** of the structure,surface morphology and electrical properties of the samples before and after ion exposure were demonstrated using powder X-ray diffraction(XRD),scanning electron microscopy(SEM)technique,and LCR *** compositional analysis was carried out using energy dispersive X-ray spectrometry(EDS).XRD results demonstrated a decrease in the intensity profile of the dominant peak by a factor of 6 showing a degradation of the ***–Hall(WH)plots reveal reduction in the grain size after irradiation along with an increase in strain and dislocation density.A decrease in the dielectric constant and loss has been recorded after ion beam exposure with reduction in ac conductivity *** contribution of grain and grain boundary effect in conduction mechanism has been addressed using Nyquist *** the samples demonstrate a lossy ferroelectric loop which shows a clear modification upon *** role of structural defects modifying the physical properties of the composite materials is discussed in this work.

关键词： Ion beam irradiation defects dielectric properties ferroelectricity.