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Journal of Alloys and Compounds 702 (2017) 479e488

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Journal of Alloys and Compounds

journal homepage: http: / /www.elsevier .com/locate/ ja lcom

Structural and electrical properties of Zinc doped Nickel ferritesnanoparticles prepared via facile combustion technique

N. Chandamma a, B.M. Manohara a, *, B.S. Ujjinappa b, G.J. Shankarmurthy c,M.V. Santhosh Kumar d

a Department of Physics, Govt. First Grade College, Davangere, 577004, Indiab Department of Physics, Govt. First Grade College for Women, Davangere, 577004, Indiac Department of Physics, UBDT College of Engineering, Davangere, 577004, Indiad Department of Physics, Jain Institute of Technology, Davangere, 577004, India

a r t i c l e i n f o

Article history:Received 20 October 2016Received in revised form26 December 2016Accepted 29 December 2016Available online 31 December 2016

Keywords:FTIRFacile combustion techniqueCubic phaseFrequencyImpedanceAC and DC conductivity

* Corresponding author.E-mail address: bmm6627@gmail.com (B.M. Mano

http://dx.doi.org/10.1016/j.jallcom.2016.12.3920925-8388/© 2017 Elsevier B.V. All rights reserved.

a b s t r a c t

Ni-Zn ferrite nanoparticles with a composition of Ni(1-x)ZnxFe2O4 (0.0 � X � 1.0) have been successfullyprepared via facile combustion technique using urea as a fuel. The structural and electrical properties ofthe samples were studied using Powder X-ray diffraction (PXRD), Scanning electron microscopy (SEM)and Fourier Infrared (FITR) Spectroscopy measurements. The PXRD analysis of all the samples shows thecubic phase without any impurity peaks. The average particle sizes were calculated by Scherrer's formulaand W-H plots were found to be in the range of (20e36) nm. The SEM image shows the agglomerationand flakes type nanoparticles with many void spaces due to exhaust of gases. FTIR spectra of the samplesshow the nature of the chemical bonds. The dielectric parameters of the prepared nanoparticles werestudied before and after g-irradiation. The dielectric constant, loss tangent and AC conductivity weredetermined as a function of frequency at RT. These properties of the samples show that they are suitablematerial for absorption of energy at higher frequencies and good materials for electromagnetic inter-ference suppression and microwave application. These dielectric properties form the basis for thetechnologies in space telecommunication and radar systems. The high D.C. resistivity and conductivityare the desired characteristics of NiFe2O4: Zn nanoparticles used to prepare Ferro fluids and magneticcoating.

© 2017 Elsevier B.V. All rights reserved.

1. Introduction

Ferrites are hard, brittle, iron containing, gray or black in colourand they are polycrystalline i.e. made up of large number of crystals.They are composed of iron oxide with one or more other metals inchemical combination. These are ferrimagnetic material whichcontains iron or iron alloys with body centered cubic crystalstructure [1,2]. A ferrite is formed by the reaction of ferric oxide(iron oxide or rust) with any number of other metals including Mg,Ba, Mn, Ni, Cu or even iron itself. A ferrite is usually described by theformula M(Fe2o4) where M represents any divalent metal thatforms divalent bonds, such as elements Mg, Ba, Mn, Ni, Cu or eveniron itself. Nickel ferrite for instance is NiFe2O4, Manganese ferriteis MnFe2O4, and both are spinel ferrites. The most familiar ferrite

hara).

known since biblical times is Magnetite (lode stone or ferrousferrite (Fe(Fe2O4)). Ferrite exhibit a form of magnetism calledferrimagnetismwhich is distinguished from the ferromagnetism ofsuch materials as Fe, Co, and Ni [3e5].

In ferrites, the magnetic moment of constituent atoms alignsthemselves in 2 or 3 different directions. A partial cancellation ofthe M-field results and the ferrite is left with an overall M-field thatis stronger than that of a ferromagnetic material. This asymmetry inthe part of the atomic orientations may be due the presence of twoor more different types of magnetic ions to a peculiar crystallinestructure. Ferrites can have different types of crystalline structureincluding spinel, garnet, perovskite and hexagonal. The mostimportant properties of ferrites include highmagnetic permeabilityand high electrical resistance. High permeability to M-field isparticularly desirable in a device such as antennas [6e8]. Highr�esistance to electricity is desirable in the core of transformers toreduce eddy currents. Ferrites of a type known as square loop fer-rites can be magnetized in either of two directions by an E-current.

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N. Chandamma et al. / Journal of Alloys and Compounds 702 (2017) 479e488480

This property makes them useful in the memory cores of digitalcomputers. Since it enables a tiny ferrite rings to store binary bits ofinformation. Another type of computer memory can be made ofcertain single crystal ferrites in which tiny M-domains calledbubbles can be individually manipulated.

Zn ferrite are series of synthetic inorganic compounds which isparamagnetic in bulk form, which becomes ferrimagnetic in nanocrystalline thin film format. The corrosion protection increases withincrease in concentration of Zinc content. Spinel type ferrites areinteresting materials due to their both magnetic and semi-conductor properties. Spinel ferrite nano materials due to theirtransition metal semiconductor properties in the last decade arefound to be used as gas sensors, photo catalytic materials and ad-sorbents for detoxication of biological fluids or removal of theheavy metals [9].

In the present work, Ni(1-x)ZnxFe2O4 nanoparticles with acompositional range 0.0 < x < 1.0 have been successfully synthe-sized via facile combustion technique using Urea as a fuel. Thismethod has an advantage in preparing multi-component materialseasily without any contaminations with desired stoichiometry.With this technique, particle size, chemical homogeneity and de-gree of agglomeration can be easily controlled. The preparedsamples were characterized using Powder X-ray Diffraction (PXRD),Scanning Electron Microscopy (SEM) and Fourier TransformInfrared Spectroscopy (FTIR). In addition to this electrical conduc-tivity, dielectric constant and dielectric loss tangent as a function offrequency before and after g - irradiated Ni (1-x) ZnxFe2O4 nano-particles were studied in detail.

2. Experimental

The Zn doped Nickel ferrites nanoparticles with nominalcompositions Ni(1-x)ZnxFe2O4 (x ¼ 0.0, 0.2, 0.4, 0.6, 0.8 and 1.0)were synthesized by a facile combustion technique. The precursorsused in this typical synthesis were analytical grade Nickel nitrate(Ni (NO3)2$6H2O), Zinc nitrate [Zn(NO3)2$6H2O], ferric nitrate[Fe(NO3)3$9H2O] and Urea (NH2CONH2). The stoichiometric ratiosof these chemicals were taken and dissolved in about 50 ml ofdeionized water in a 500 ml borosil beaker and were stirred withmagnetic stirrer for 30 min. The homogeneous mixture wasrapidly heated in a preheated electric Muffle furnace (Technico labproduct, Chennai) maintained at 500 ± 10 �C [10e12]. The reactionmixture boils and undergoes thermal dehydration, followed bysmoldering with the liberation of gaseous (N2 and CO2) and pro-duce foamy, voluminous fine brownish coloured Ni (1-x) ZnxFe2O4nanoparticles. The chemical reaction of synthesis process is rep-resented by

ð1� xÞZn ðNO3Þ2 þ xNiðNO3Þ2 þ 2Fe ðNO3Þ3þNH2CONH2/Znð1�xÞNixFe2O4þ 41N2þ26CO2þ52H2O

(1)

2.1. Measurements

The structural characterization of all samples were carried outby PAN analytical X'pert PRO MPD Instrument with graphite-filtered CuKa radiation (l ¼ 1.541 Å), Germany. The data wascollected in the range of 20

�< 2q < 70

�with the scan rate of 0.033�/

sec. The surface morphology of the prepared samples (pellets) wascharacterized by a SEM (JEOL JSM 6390LV). FTIR spectra were takenon Perkin Elmer Spectrometer (spectrum 1000) with KBr pelletswas used for monitoring the structural changes of the synthesizedsamples from 4000 to 400 cm�1. Highly polished pellets of

dimensions (13mm� 2mm)with a thin layer of silver paste coatedfor electrical contact were used for measurements. The pellets wereirradiated by g - rays with dose of 5 Mega rad (50 kGy/h) at theeffective dose rate of 4.97 kGy/h at room temperature (RT) for 10 husing Gamma source Co60 (1.25 Mev). The dielectric constant,dielectric loss and A.C. response measurements were made at RTusing Hioki model 3532-50 programmable Computer (Japan)interfaced with a digital LCR meter before and after g - rays irra-diation. DC conductivity is measured by Keithley 2361 Triggercontroller and Keithley 236 source meter unit before and after g -rays irradiated pellets.

3. Results and discussion

3.1. Powder X-ray diffraction

The PXRD pattern of Ni(1-x)ZnxFe2O4 nanoparticles (x ¼ 0.0, 0.2,0.4, 0.6, 0.8 and 1.0) synthesized samples are shown in Fig. 1 (aef).From the PXRD pattern, it has been observed that all the reflectionpeaks of undoped as well as Zn doped compound matches wellwith Joint Committee for Powder Diffraction Set (JCPDS) CardNumber 52-0278 for nickel ferrite. Furthermore, there is no im-purity peaks for all the compositions, which indicate that all thesamples crystallize in cubic phase with space group of Fd3 m (227)[13]. The average crystallite size was obtained from the mostprominent PXRD peaks using Debye-Scherrer's formula [14].

d ¼ k lb cos q

(2)

where, d is the average particle size, k is a constant lies between(0.88e0.92), the average value taken as 0.9 in the calculation, l iswavelength of Cu-Ka irradiation (l ¼ 1.541 A�), b is the full width athalf maximum intensity of the diffraction peak and q is thediffraction angle. The particle size of the prepared samples is in therange of (20e28) nm.

Further, effective particle size and strain present in the Ni (1-x)ZnxFe2O4 nanoparticles was estimated using the W-H equation.

b cos q ¼ klD

þ 4ε sin q (3)

where ‘ε’ is the strain associated with the nanoparticles. The aboveequation represents a straight line plotting the graph of ‘b cosq’verses ‘4sinq’. The effective particle size for which the lattice strainhas been taken into account can be estimated from the extrapola-tion of the plot as shown in Fig. 2 (aef). From the W-H plots, thelattice strain is extracted from the slope and the crystalline size wasextracted from the y-intercept of the linear fit [15]. The averagecrystallite size was in the range of (30e36) nm, well matched withthe Scherrer's formula. Lattice strain of Ni (1-x) ZnxFe2O4 nano-particles is in the range of (3.88e4.71) � 10�3 as shown in Table 1.

3.2. Morphological studies

The SEM photographs for Ni(1-x)ZnxFe2O4 nanoparticles (x¼ 0.0,0.2, 0.4, 0.6, 0.8 and 1.0) as shown in Fig. 3 (aef). It is to be notedthat, the grain size and the size of the samples prepared by thecombustion method are much smaller than those for samplesprepared by the conventional method. The micrograph of thesamples shows that surface morphology is full of small grains andbig pores complex, more like foam. The surface of the powdershows pores created by the escaping gases during the combustionreaction.

Fig. 1. (aef). PXRD of (0.0e1.0) Zn doped NiFe2O4 nanoparticles.

Fig. 2. (aef). Williamson-Hall plots of (0.0e1.0) Zn doped NiFe2O4 nanoparticles.

N. Chandamma et al. / Journal of Alloys and Compounds 702 (2017) 479e488 481

3.3. FT-IR spectral analysis

In order to investigate the nature of the chemical bonds formedin the prepared sample, FTIR spectrumwas recorded in the range of4000e400 cm�1 shown in Fig. 4(aef). The FTIR bands of solids areusually assigned to vibration of ions in the crystal lattice present inthe 943 and 1340 cm�1 [16]. Generally the highest one observed inthe 538 cm�1, corresponds to intrinsic stretching vibrations of themetal at the tetrahedral site which is for Zn2þ because of itscapability to form covalent bonds involving sp3 hybridization.Whereas the lowest band observed in the 405 cm�1 is assigned tooctahedral-metal stretching. The band observed at 2341 cm�1

ascribed to the stretching modes and H-O-H bending vibration ofthe free or absorbed water due to the trapped un-burnt carbonylcompounds during combustion process [17]. FTIR spectrum sup-ports for the formation of undoped sample because the peakscorrespond to the impurities like NO3�, CO2 and absorbed water arevery weak in nature. It is confirmed that only localized burning hasoccurred without the presence of oxidant (ammonia) that helps tostart high temperature self-propagation reaction.

3.4. Dielectric studies

3.4.1. Dielectric constant and loss tangentThe frequency dependent dielectric constants like impedance

(Z), resistance (R), resistivity (r), real and imaginary part of

Table 1Estimated structural parameters of (0.0e1.0) Zn doped NiFe2O4 nanoparticles.

Zn concentration Scherer's equation (nm)

0.0 200.2 250.4 240.6 280.8 251.0 30

dielectric permittivity ( 3) of Ni(1-x)ZnxFe2O4 nanoparticles (x ¼ 0.0,0.2, 0.4, 0.6, 0.8 and 1.0) at RT were shown in Fig. 5 (aef) before g-irradiation and Fig. 6 (aef) after g - irradiation. The sample exhibitthe dielectric dispersion where dielectric constant decreases as thefrequency increases from 10 Hz to 5 MHz. The values of dielectricconstant at lower frequency are found to be about 600e1000 for100 Hz. Frequency dependent permittivity is because of atomic andelectronic polarization. Fe3þ ions have a spherical symmetry of thecharge electron cloud due to a stable d-shell configuration whereasFe2þ ions have extra electron which perturb the symmetry of thecharge electron cloud. Therefore, the presence of Fe2þ ions in theferrite sample increases polarization and hence permittivity. Whenfew Fe2þ ionswere replacedwith some dopants like zinc, cobalt etc,and the dielectric permittivity changes drastically [18]. Figs. 5 and 6shows that both real (ε0) and imaginary (ε0 0) permittivity valuesdecreases with increase in frequency [19]. The complex dielectricpermittivity of the Ni(1-x)ZnxFe2O4 nanoparticles (x ¼ 0.0, 0.2, 0.4,0.6, 0.8 and 1.0) before and after g - irradiation is

ε* ¼ ε0 þ ε00 (4)

where, ε0 and ε0 0 are the real and imaginary parts of the complex

W-H plot (nm) Lattice strain ε � 10-3

30 4.7132 4.5433 4.0035 4.5332 3.8134 3.88

Fig. 3. (aef). SEM images of (0.0e1.0) Zn doped NiFe2O4 nanoparticles.

Fig. 4. (aef). FTIR of (0.0e1.0) Zn doped NiFe2O4 nanoparticles.

N. Chandamma et al. / Journal of Alloys and Compounds 702 (2017) 479e488482

dielectric permittivity.The larger value of permittivity at lower frequencies is due to

atomic, electronic, ionic, interfacial, and grain boundary which is inaccordance with MaxwelleWagner theory [20e22]. At higher fre-quencies, the frequency of electron/hole exchange is not able tofollow the applied electric field, thus, resulting in decrease of ionicand orientation polarizability which leads to decrease in permit-tivity. The higher frequency dielectric constant is attributed to ionicand electronic polarizations that are independent of frequency. Thisis in accordance with Rezlescue model [23].

3.5. A.C. Conductivity studies

The variation of A.C. conductivity of Ni(1-x)ZnxFe2O4 nano-particles (x ¼ 0.0, 0.2, 0.4, 0.6, 0.8 and 1.0) was studied at differentfrequencies are represented in Fig. 7 (aef) before and Fig. 8 (aef)after g - irradiations. It is observed that, as the frequency of theapplied field increases, hopping of carriers also increases, thereby,increasing conductivity shown in Fig. 7 (aef) before and Fig. 8 (aef)

N. Chandamma et al. / Journal of Alloys and Compounds 702 (2017) 479e488 483

after g - irradiations. The conductivity increases in the g-irradiatedsamples with respect to the frequency. The increase in A.C con-ductivity with frequency could also be explained on the basis of theKoops model [24]. According to this model, low frequency con-ductivity is due to grain boundaries, while scattering at higherfrequencies is due to conducting grains. Since, the high density ofinterfacial states in the nano system can serve as charge carriersdue to ionization and can also function as conduction centres fortransport of charge carriers. The A.C. conductivity in these systemsis at variance with respect to the bulk and the conductivity is foundto be higher [25,26]. Hence, in the present studies the variation ofA.C. conductivity with frequency may also be attributed to

Fig. 5. (aee) Dielectric studies of (0.0e1.0) Zn dop

conduction by small polarons.The variations of dielectric loss tangent {tan (d)} with frequency

for the sample is shown in Fig. 7 (aef) before and Fig. 8 (aef) after g- irradiations. In this case, dielectric loss tangent was less in after g-irradiation. The dielectric losses are mainly due to the ion migra-tion, where conduction losses are of most significant. The tan(d)peak is expected when the hopping frequency of the electron be-tween Fe2þ and Fe3þ ions is approximately equal to that of theexternal applied electric field. The peak is the result of resonancedue to the matching of the time period of the applied electric fieldwith those of the corresponding relaxation phenomena. This peakis observed at high frequency range of about 10 � 104 Hz and the

ed NiFe2O4 nanoparticles before g-irradiated.

Fig. 6. (aee) Dielectric studies of (0.0e1.0) Zn doped NiFe2O4 nanoparticles after g-irradiated.

N. Chandamma et al. / Journal of Alloys and Compounds 702 (2017) 479e488484

loss value corresponds to 0.7 and 1.09 respectively before and afterg-irradiations. At frequency of 10 Hz, the loss is 0.3 and 4 respec-tively before and after g-irradiations. Relaxation of dipoles underan electric field is decreased with increasing frequency and ulti-mately results in a decrease in dielectric loss.

The dissipation factor or the loss factor of Ni(1-x)ZnxFe2O4nanoparticles (x ¼ 0.0, 0.2, 0.4, 0.6, 0.8 and 1.0) before and after g -irradiation is represented as

tand ¼ ε00

ε0 (5)

There is a normal trend of dielectric loss without any peakingbehavior. It may be due to the fact that the resonancematchingmaybe beyond the analyzed frequency range. Hence there is no power

loss due to the transfer of energy from applied field to the oscil-lating ions within the studied frequency range.

The conduction mechanism, the A.C. conductivity can be eval-uated from the dielectric permittivity and dielectric loss as

sac ¼ ε0ε0utand (6)The A.C. conductivity increases as the frequency of applied field

increases. The variation of A.C. conductivity could be explained interms of low frequency and high frequency regions. In low fre-quency region, grain boundaries are found to be more active so thatthe probability density of charge carriers is less whereas; in highfrequency region, conducting grains are more active promotingcharge carriers. The total conductivity of ferrites is,

Fig. 7. (aed) AC Conductivity of (0.0e1.0) Zn doped NiFe2O4 nanoparticles before g-irradiated.

N. Chandamma et al. / Journal of Alloys and Compounds 702 (2017) 479e488 485

sðu1 TÞ ¼ sdc ðTÞ þ sac ðu1 TÞ (7)

where, sdc is the D.C. conductivity due to less conduction, sac is theA.C. conductivity due to electron hopping between the Ni2þ andFe2O4 sites.

Figs. 7 and 8 shows the variation of elastic moduli (M0 and M00)with frequency supports the trend of tan (d) variation. All the termsfollow the decreasing trend with frequency which is due to thepresence of increased charge carriers like electrons, holes and po-larons. A good dielectric material is one which has high dielectricconstant and high quality factor (Q � f) or low dielectric loss value.So these compounds can be considered as good dielectric materialsand good materials for electromagnetic interference suppressionand microwave application. These properties form the basis for thetechnologies in space telecommunication and radar systems.

3.6. D.C. Conductivity studies

The D.C. electrical resistivity is one of the useful characterizationtechniques to understand conductivity mechanism. The D.C. re-sistivity of the samples is estimated by varying the voltage andrecording the current for the (x ¼ 0.0, 0.2, 0.4, 0.6, 0.8 and 1.0)before and after g - irradiation (Samples of Ni(1-x)ZnxFe2O4 nano-particles in the form of pellets of diameter 6.5 mm also, thickness2 mm). To study the semiconducting nature of prepared pellets, theD.C. electrical conductivity was determined from the D.C. I-Vcharacteristics for each sample at RT, using Ohm's law. As thevoltage increases, current also increases at RT. The reciprocal of the

slope of the linear fitting data gives resistance of the Ni(1-x)ZnxFe2O4nanoparticles (x ¼ 0.0, 0.2, 0.4, 0.6, 0.8 and 1.0) before and after g -irradiation samples shown in the Fig. 9. The resistivity of the samplewere calculated using the relation,

r ¼ RA=l Um (8)

where R; Resistance of the sample, A: Surface area of the

sample ¼ p�d24

�, d: diameter of the pellets and l; Thickness of the

pellets.As the concentration of Zn increases the resistivity decreases

and it is shown in Fig. 10. D.C electrical resistivity of the samplesafter g - irradiation decreases more than the before g - irradiatedsamples with increasing the dopant Zn2þ concentration fromx¼ 0.0 to x¼ 1.0. The decrease in resistivitymay be due to presenceof Fe2þ ions [27,28]. Another reason for decrease in resistivity onincreasing zinc composition is due to that Zn2þ ions prefer theoccupation of tetrahedral sites (A) and Ni ions prefers the occupa-tion of octahedral sites (B). While Fe2þ ions partially occupies A andB sites. On increasing Zn2þ dopant concentration at A sites, hostmaterial Ni ions concentration at B sites will be decrease. This leadsto migration of some Fe ions from A site to B site to balance thereduction in Ni ions concentration at B sites. As a result, the numberof ferric and ferrous ions at B sites which are responsible for elec-trical conductivity in ferrites increases consequently resistivitydecreases by increasing Zn2þ dopant ion concentration [29,30]. TheDC electrical conductivity measured is shown in Fig. 11. This graph

Fig. 8. (aed) AC Conductivity of (0.0e1.0) Zn doped NiFe2O4 nanoparticles after g-irradiated.

Fig. 9. VeI Plots of DC Conductivity (a) before g-irradiated and (b) after g-irradiated (0.0e1.0) Zn doped NiFe2O4 nanoparticles.

N. Chandamma et al. / Journal of Alloys and Compounds 702 (2017) 479e488486

Fig. 10. Resistivity verses Zn composition of DC Conductivity (a) before g-irradiatedand (b) after g-irradiated (0.0e1.0) Zn doped NiFe2O4 nanoparticles.

Fig. 11. Conductivity verses Zn composition of DC Conductivity (a) before g-irradiatedand (b) after g-irradiated (0.0e1.0) Zn doped NiFe2O4 nanoparticles.

N. Chandamma et al. / Journal of Alloys and Compounds 702 (2017) 479e488 487

shows that by increasing Zn2þ dopant concentration, conductivityalso increases. DC conductivity of the Ni(1-x)ZnxFe2O4 nanoparticles(x¼ 0.0, 0.2, 0.4, 0.6, 0.8 and 1.0) after g - irradiation samples higherthan the before g - irradiation samples as shown in Table 2. Thisconforms that the ferrite under investigation has semiconductorbehavior. Hence g - irradiation samples are suitable material forhigh D.C. resistivity and conductivity are the desired characteristics

Table 2DC Resistivity and Conductivity of before and after g-irradiated (0.0e1.0) Zn dopedNiFe2O4 nanoparticles.

Composition(X) of

NiFe2O4:Zn

Resistance,R � 106 (U)

Resistivity,r ¼ RA/t X 106 (Um)

Conductivity,s ¼ 1/r X 10-6

(U-1 m-1)

Before g-irradiated

After g-irradiated

Before g-irradiated

After g-irradiated

Before g-irradiated

After g-irradiated

0.0 18 13 0.29 0.21 3.39 4.820.2 16 11 0.27 0.19 3.69 5.410.4 14 10 0.23 0.18 4.27 5.970.6 14 10 0.22 0.16 4.40 6.230.8 11 7 0.18 0.12 5.44 8.501.0 11 6 0.17 0.10 5.64 9.68

of NiFe2O4: Zn nanoparticles used to prepare Ferro fluids andmagnetic coating.

4. Conclusion

The samples of Ni (1-x) ZnxFe2O4 nanoparticles (x ¼ 0.0, 0.2, 0.4,0.6, 0.8 and 1.0) were successfully synthesized by facile combustiontechnique. PXRD patterns reveal that the synthesized samples werecubic phase structure having crystalline sizes in the range (20e36)nm. The dielectric dispersion with frequency was observed andsuccessfully explained on the basis of Maxwell-Wagner theory ofinterfacial polarization in consonance with the Koops phenome-nological theory. The lower value of dielectric loss for a samplehaving equal concentrations Zn2þ dopant and Ni2þ host materialmakes them suitable material for electromagnetic interferencesuppression, telecommunication, radar systems and microwaveapplication. The high D.C. resistivity and conductivity are thedesired characteristics of NiFe2O4: Zn nanoparticles used to prepareFerro fluids and magnetic coating.

Acknowledgements

The authors are grateful to the Principal, Head of the Depart-ment of Physics and staff, Government First Grade College,Davangere, for their constant support and encouragement. Theauthor N. Chandamma thanks to UGC (Project no.-1402/14-15/KADA008/UGC-SWRO dated 04th Feb 2015) for financial support forsanction the Minor research Project.

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Structural and electrical properties of Zinc doped Nickel ferrites nanoparticles prepared via facile combustion technique1. Introduction2. Experimental2.1. Measurements

3. Results and discussion3.1. Powder X-ray diffraction3.2. Morphological studies3.3. FT-IR spectral analysis3.4. Dielectric studies3.4.1. Dielectric constant and loss tangent

3.5. A.C. Conductivity studies3.6. D.C. Conductivity studies

4. ConclusionAcknowledgementsReferences