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Structural,dielectric and electrical properties of bismuth magnesium tantalate electronic system

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Journal of Magnesium and Alloys 2019年第4期7卷 628-636页

作者： Sarbasri Halder Satyanarayan Bhuyan r.n.p.choudhary Department of Electronics and Communication Engineering Siksha‘O’AnusandhanDeemed to be UniversityBhubaneswar 751030India Department of physics Siksha‘O’AnusandhanDeemed to be UniversityBhubaneswar 751030India

The lead-free dielectric compound Bi(Mg2/3Ta1/3)O3(BMT)has been synthesized at high temperature by a low-cost solid-state *** X-ray diffraction(XrD)technique reveals that the fabricated sample has an orthorhombic crystal *** scanning electron microscope(SEM)image displays the uniform distribution of grains on the surface of the *** dielectric parameters(permittivity(εr),and loss tangent(tanδ)are studied over a wide range of temperature(150-500℃)and frequency(1 kHz-1 MHz).The temperature dependent conductivity plot follows Universal Johnson’s power *** complex impedance and modulus spectrum illustrate the electrical behavior of the compound at various frequency and *** nyquist spectra show the presence of the effect of grain and grain boundary in the synthesized *** grain resistance value declines with the rise in temperature that shows the presence of a negative temperature coefficient(nTCr)behavior in the *** complex modulus spectra display the occurrence of the conduction mechanism in the *** reported compound has a relative dielectric constant and loss of 22×10^3 and 1.8 respectively at 1 kHz frequency and 500℃,thus becoming an efficient applicant for dielectric applications that can operate at higher temperatures.

关键词： XrD Impedance spectroscopy Conductivity Conduction

Development of lead-free multifunctional materials Bi(Co_(0.45Ti0.45Fe0.10)O3

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progress in natural Science:Materials International 2018年第3期28卷 308-314页

作者： nitin Kumar Alok Shukla r.n.p.choudhary Department of physics National Institute of Technology Mizoram Department of physics Siksha ‘O′Anusandhan University

A lead free multiferroic material,Bi(Co0.45Ti0.45Fe0.10)O3（BCTF45/10）was synthesized by a solid-state reaction route at high ***45/10 powder was prepared using appropriate raw maretials in oxide powders with methanol ***-prepared circular shaped pellets were sintered at 1053 K for 6 h to produce a compact *** structural properties and elemental analysis were determined using X-ray diffraction and energy-dispersive X-ray spectroscopy techniques respectively at room *** microstructure or surface morphology of the sintered sample was carried out by using field emission scanning electron microscope（FE-SEM）.The XrD analysis shows that the compound exhibits the single-phase of orthorhombic *** average crystallite size estimated using the Scherrer's technique was found to be 30 *** influence of Co and Ti substitution（at Bi and Ti sites of Bi Fe O3）on some physical and electrical properties of Bi Fe O3was examined by using phase sensitive multimeter in a wide frequency and temperature *** magnetic nature of the sample was studied using vibrating sample *** of room temperature magnetic hysteresis loop exhibits the enhanced ferromagnetic characteristic with saturation magnetization of 5.091 emu/g and coercive field of 0.213 k Oe *** enhanced magnetic properties highlight various potential applications of Co/Ti doped BCTF45/10 materials.

关键词： Multifunctional material Dielectric constant and loss Electrical characteristics Impedance spectroscopy

Electrical properties of rare earth based tungsten bronze vanadates

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Journal of rare Earths 2012年第11期30卷 1134-1137页

作者： B.B.Mohanty p.S.Sahoo r.n.p.choudhary Department of physics Betnoti College Betnoti Department of physics ITEr

Barium based tungsten bronze （TB） oxides having high dielectric constant and low loss, can be effectively used as transducers, actuators, capacitors and also in memory devices. All these characteristics stimulated the researchers to replace toxic and hazardous lead based materials by barium based TB materials from industry. In the present research work, polycrystalline samples of BaaSrrTi3VTO30 （r=Dy, Sm, La） were synthesized by a high temperature solid state reaction technique. preliminary structural （X-ray diffraction） analyses of these com- pounds showed the formation of single-phase orthorhombic structures at room temperature having average crystallite size of the order of some nanometer for all the compounds. The scanning electron micrographs （SEM） provided information on the quality of the samples and showed more or less homogeneous distribution of grains over the entire surface of the samples. Detailed dielectric study in a wide temperature range （30-500 ℃） showed ferro to para phase transition for Dy and Sm substituted samples whereas no such transition was observed for La substituted samples. Both the grain and grain boundary resistances exhibited negative temperature coefficient of resistance behavior much like semiconductors. The dc conductivity of all the compounds obeyed Arrhenius relation.

关键词： ceramics X-ray diffraction dielectric properties electrical conductivity rare earths

Study of multiferroic properties of Bi_(2)Fe_(2)WO_(9) ceramic for devices application

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Journal of Advanced Dielectrics 2016年第3期6卷 64-71页

作者： Jyoshna rout r.n.p.choudhary Department of physics Institute of Technical Education&Research Siksha‘`O'Anusandhan UniversityBhubaneswar 751030OdishaIndia

The Bi_(2)Fe_(2)WO_(9) ceramic was prepared using a standard solid-state reaction *** analysis of X-ray diffraction pattern revealed the formation of single-phase compound with orthorhombic crystal *** surface morphology of the material captured using scanning electron microscope(SEM)exhibits formation of a densely packed *** study of dielectric properties showed two anomalies at 200℃and 450℃:first one may be related to magnetic whereas second one may be related to ferroelectric phase *** field dependent magnetic study of the material shows the existence of small remnant magnetization(M_(r))of 0.052 emμ/g at room *** existence of magneto-electric(ME)coupling coefficient along with above properties confirms multi-ferroic characteristics of the *** range temperature and frequency dependent electrical parameters(impedance,modulus,conductivity)of the compound shows that electric properties are correlated to its *** studies of frequency dependence of ac conductivity suggest that the material obeys Jonscher's universal power law.

关键词： X-ray diffraction magnetism ferroelectric properties magneto-electric coupling impedance modulus

Electrical properties of na_(2)pb_(2)r_(2)W_(2)Ti_(4)V_(4)O_(30)(r=Dy,pr)ceramics

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Journal of Advanced Ceramics 2013年第2期2卷 112-118页

作者： piyush r.DAS B.n.pArIDA r.pADHEE r.n.p.choudhary Department of physics Institute of Technical Education&ResearchSiksha‘O’Anusandahan UniversityKhandagiriBhubaneswar 751030OdishaIndia

The polycrystalline samples of complex tungsten bronze(TB)na_(2)pb_(2)r_(2)W_(2)Ti_(4)V_(4)O_(30)(r=Dy,pr)compounds were prepared by solid-state reaction ***-temperature preliminary structural studies confirm the formation of the compounds in the orthorhombic crystal *** studies of electrical properties of the materials using complex impedance spectroscopy technique exhibit that the impedance and related parameters are strongly dependent upon temperature and microstructure(bulk,grain boundary,etc).An observation of negative temperature coefficient of resistance(nTCr)suggests the materials have semiconducting *** variation of AC conductivity with temperature shows a typical Arrhenius behavior of the *** the samples obey Jonscher’s universal power *** existence of hopping mechanism in the electrical transport processes in the system with non-exponential type of conductivity relaxation is confirmed by electrical modulus analysis.

关键词： ceramics impedance spectroscopy electrical properties ferroelectricity microstructure

Dielectric and electrical properties of na_(2)pb_(2)La_(2)W_(2)Ti_(4)Ta_(4)O_(30) electroceramics

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Journal of Advanced Ceramics 2012年第3期1卷 232-240页

作者： p.r.DAS S.BEHErA r.pADHEE p.nAYAK r.n.p.choudhary Department of physics Institute of Technical Education&ResearchSiksha‘O’Anusandhan UniversityBhubaneswar-751030OdishaIndia Department of physics Hi-tech College EngineeringBhubaneswar-75102OdishaIndia School of physics Sambalpur UniversityJyoti ViharBurla-768019OdishaIndia

The polycrystalline sample of complex tungsten-bronze type compound(na_(2)pb_(2)La_(2)W_(2)Ti_(4)Ta_(4)O_(30))was prepared by a high-temperature solid-state reaction *** temperature preliminary structural study using X-ray diffraction(XrD)data exhibits the formation of a single-phase new *** SEM micrograph of the compound exhibits non uniform rectangular grains distributed throughout the sample *** studies of dielectric parameters(εr,tanδ)as a function of temperature and frequency,and p-E hysteresis(spontaneous polarization)confirmed the existence of ferroelectricity in the *** impedance spectroscopy analysis,carried out as a function of frequency at different temperatures,established a correlation between the microstructure and electrical properties of the *** electrical relaxation process occurring in the material is temperature *** activation energy found from the Arrhenius plot that the conduction process in the material is of mixed *** nature of frequency dependence of ac conductivity suggests that the material obeys Jonscher’s universal power law.

关键词： electronic material ferroelectricity XrD electrical conductivity

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

Impedance spectroscopy study of na_(2)SmV_(5)O_(15) ceramics

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Journal of Advanced Ceramics 2014年第1期3卷 1-6页

作者： p.S.DAS p.K.CHAKrABOrTY Banarji BEHErA n.K.MOHAnTY r.n.p.choudhary Department of physics Midnapore CollegeMidnapore 721101India School of physics Sambalpur UniversityBurla 768019SambalpurOdishaIndia Department of physics ITERSiksha“O”Anusandhan UniversityBhubaneswar 751030OdishaIndia

The polycrystalline na_(2)SmV_(5)O_(15)(nSV),a new member of the tungsten bronze(TB)family,was prepared by a mixed-oxide *** room-temperature X-ray diffraction(XrD)confirmed the formation of single phase compound with orthorhombic crystal *** scanning electron microscopy(SEM)analysis indicated that the compound has homogeneous micrograph with a uniform distribution of small grains over the entire surface of the *** analysis of impedance spectra of nSV in a low-temperature range(-100℃to 100℃)at different frequencies exhibited interesting electrical properties like the contribution of bulk effect in conduction *** study of imaginary part of the impedance at different temperatures showed existence of relaxation peak with its shift towards higher frequency on increasing *** suggested the presence of frequency and temperature dependent relaxation process in the *** loss peak spectra were found to abide by Arrhenius law with small activation energy of 0.12 *** temperature dependence of AC and DC electrical conductivity(σ_(AC) and σ_(DC))was also obtained.

关键词： solid-state reaction microstructure impedance conductivity

Dielectric response and pyroelectric properties of lead-free ferroelectric Ba_(3)(VO_(4))_(2)

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Journal of Advanced Dielectrics 2015年第1期5卷 43-49页

作者： Biswajit pati r.n.p.choudhary piyush r.Das B.C.Sutar Department of physics J.K.B.K.Government CollegeCuttack 753004India Department of physics Institute of Technical Education and Research Siksha O Anusandhan UniversityBhubaneswar 751030India Department of physics Veer Surendra Sai University of Technology BurlaSambalpur 768018India Department of physics Hi-Tech College Engineering Bhubaneswar 751025India

The current paper presents results of dielectric response,pyroelectric behavior and conductivity study of lead-free ferroelectric barium orthovanadate(Ba_(3)(VO_(4))_(2)or Ba_(3)V_(2)O_(8))ceramic,for a wide range of temperature and *** X-ray diffraction study suggests the formation of a single-phase compound in trigonal crystal *** SEM micrograph of gold-coated pellet sample shows well-defined and homogeneous *** studies of dielectric parameters(ε_(r)and tanδ)of the compound as a function of temperature and frequency reveal their independence over a wide range of temperature and *** nature of polarization versus electric field(p-E)hysteresis loop of Ba_(3)V_(2)O_(8)at room temperature suggests its ferroelectric *** temperature dependence of pyroelectric coefficient and figure of merits of the sample support its dielectric *** nature of variation of dc conductivity with temperature confirms the Arrhenius and negative temperature coefficient of resistance(nTCr)behavior of the material.

关键词： X-ray diffraction palmierite structure dielectric properties pyroelectric properties