synthesis and characterization of structural, magnetic and ... no. 1 2018...zn ferrites play a vital...

InternationalJournalofNanoelectronicsandMaterialsVolume 11, No. 1, Jan 2018 [15-24]

SynthesisandCharacterizationofStructural,MagneticandElectricalPropertiesofNi–Mn–ZnFerrites

HosneyAraBegum1,a,NaziaKhatun1,b,*,SuraviIslam1,c,NurzamanAraAhmed1,d,Mohammad

SajjadHossain1.e,MohammadAbdulGafur2,fandAyeshaSiddika2,g

1IndustrialPhysicsDivision,BCSIRLaboratories,Dhaka.Bangladesh.2IFRD,BCSIR,Dhaka,Bangladesh.

Received20April2017;Revised13June2017;Accepted25Aug2017

ABSTRACT

Polycrystalline ferrites(NiXMnZn1−XFe2O4)weresynthesizedbyaconventionalceramicmethodandsinteredat1100°Cfor4hours.Thestructureandsurfacemorphologyofthesamples were characterized by X‐ray diffraction (XRD) and scanning electronmicroscopy (SEM) analyses. Frequency‐dependent permeability (μ′), conductivity (σ),qualityfactor(Q),dielectricloss(tanδ),anddielectricconstant(ε′)ofthesamplesweremeasured by impedance analyzer. DC resistivity and activation energy were alsodetermined. Activation energy was calculated by Arrhenius‐type resistivity plots.Analysis of themicrostructure of theprepared sample showed that the average grainsize increased with increasing nickel (Ni) content. Based on the XRD patterns, thepreparedsamplesshowedacubicspinelstructureandanaveragecrystallinesizeof46nm.Keywords: Microstructure, Grain size, Curi temperature (Tc), Dielectric Constant (ε′)andConductivity(σ).

1. INTRODUCTIONSincethediscoveryofferrites,thedesignandsynthesisofferriteshavebeenthefocusofintensefundamentalandappliedresearchassuchtoimprovethephysicalpropertiesofferrite.Ferritematerials are widely used in electronic devices such as sensors, memory storing apparatus,electromagneticgadgets,andactuators.Softmagneticferritessuchasthosebasedonoxides,arethemost important [1]. Scholarshave reportedon theadvantagesofnano‐crystalline ferritesparticularly nano‐sized zinc that interacts with other mixed ferrites [2,3].The magnetic andelectricproperties [4]of thesematerialshavegained increasingresearchattention[5].Mn–Znferrites are extensively used in electronics due to high saturation magnetization, magneticpermeability,anddielectricresistivityandlowcorelosses[6,7].SimilartoMn–Znferrites,Ni–Znferritesplayavitalroleinthetechnologicalfield.The combination of the Mn–Zn and Ni–Zn, namely, Ni–Mn–Zn ferrite, may produce goodmagneticpropertiesandcanbeappliedinhighfrequencyregions[8].Thedielectricpropertiesof Ni–Mn–Zn ferrites should be further studied considering only few works have beenconducted on thesematerials [9]. These ferrites can be synthesized through co‐precipitation,hydrothermal process, solution–gel technique, high‐energy ball milling, and conventionalceramic method [10–15]. In the present work, conventional ceramic method was used for

*Correspondingauthor:NaziaKhatun,ScientificOfficer,IndustrialPhysicsDivision,BCSIRLaboratories,Dhaka,Dhaka‐1205,Bangladesh.E‐mail:[email protected]

HosneyAraBegum,etal./SynthesisandCharacterizationofStructural,Magnetic…

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synthesis.Thedensity,porosity,andinitialpermeabilityofNiXMnZn1−XFe2O4weresystematicallyevaluatedto investigate theelectricandmagneticpropertiesofNi–Mn–Znferritesandextendtheirapplicationinhighfrequencyregions.2. MATERIALSANDMETHODSPolycrystallineNiXMnZn1−XFe2O4waspreparedthroughasimpleconventionalceramicmethod.Analytical‐grademanganeseoxide(MnO2),nickeloxide(NiO),zincoxide(ZnO),andferricoxide(Fe2O3)wereusedasrawmaterials.Stoichiometricamountsofrawmaterialsweremixedinasoggymedium to facilitate homogeneousmixing. Aluminum balls were used to prevent ironcontamination, and ethanol was added to form homogeneous slurry. The samples werepulverizedthroughaplanetaryballmillfor8hours.Theweightratiooftheballtopowderwas10:1.Themilledsampleswerecalcinedinafurnaceat700°Cfor3hoursinthepresenceofair.Thedriedpowderwasballmilledfor2hours.Thegroundferritepowderwasplasticizedwithan aqueous solution of 4% polyvinyl alcohol (PVA) as binder. The resulting materials werepressedintopelletsandtoroidalshapebyapplying3±0.5MPafor1minute.Thesampleswerethensinteredat1100°Cfor4hours.3. RESULTSANDDISCUSSION

NiXMnZn1−XFe2O4 ferriteswerecharacterizedbyX‐raydiffraction (XRD)andscanningelectronmicroscopy (SEM) analyses.TheXRDanalysis showeda singlephasepatterns indicating thatthesample is ferritewithacubicspinelstructure.AllXRDpeak inFigure1 isat(220),(311),(222),(400),(422),(511),and(400)planes.Generally, the intensityof theXRDpeakchangeswhen the structure is altered. Such changes also depend on the atomic position, type andquantity in the cell. In addition, grain size, grain surface relaxation and temperature alsoinfluencethevariationsinthepeakintensity.

25 30 35 40 45 50 55 60 65 70

x=0.2

x=0.4

x=0.6

x=0.8

(440

)

(511

)

(422

)

(40

0)

(222

)

(220

)

Inte

nsi

ty

2 Theta

(31

1)

Figure1.XRDpatternofNiXMnZn1−XFe2O4(wherex=0.2,0.4,0.6,0.8)ByusingtheDebyeScherrerequationinEq.(1),theaveragecrystallitesizecanbedeterminedfromthe(311)diffractionpeak,whichexhibitedthehighestintensity.

.

(1)


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where isthewavelengthofX‐ray(1.5406Å), isthefullwidthathalfmaximum(inradians),andθ is theBragg’sangle.The latticeparameterof the cubic sampleswas calculated fromd‐spacingcorrespondingtothestrongestpeak(311)accordingtothefollowingrelation:

(2)whereh,k,andlrepresenttheMillerindicesofthecrystalplanes.

Table 1 shows the lattice constant, X‐ray density, bulk density, and porosity of thesamples. The lattice parameters of all samples were plotted against Ni content as shown inFigure 2. Results indicate that the lattice constant decreasedwith increasingNi content. ThelatticeparameterwasthenusedtocalculateX‐raydensity.

Figure2.VariationinthelatticeconstantwithNicontent

TherelationbetweenX‐raydensity, andlatticeconstant,aisasfollows:

(3)

whereNistheAvogadro’snumber(6.023×1023m−1),andMisthemolecularweight.Theactualdensity of the ferrite sampleswas determined using the Archimedes’ principle. The porosity(%P)ofthesampleswasthencalculatedusingthefollowingequation:

P=(1− / ×100(4)where istheactualdensityofthesampledeterminedusingtheformulainEq.(5):

= (5)wheremisthesampleweight,andvisthesamplevolume.

8.395

8.4

8.405

8.41

8.415

8.42

8.425

8.43

8.435

8.44

8.445

0 0.2 0.4 0.6 0.8 1

lattice constan

t a in Å

Ni content, x


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Table1Latticeconstant,X‐raydensity,bulkdensity,andporosityofthesamples

Nicontent latticeconstanta

inÅX‐raydensity,gm/cc

Bulkdensity,gm/cc

Porosity,P(%)

X=0.2 8.4336 6.1928 4.9554 19.9798X=0.4 8.4328 6.1649 4.9554 18.0408X=0.6 8.4197 6.1639 4.9699 19.3708X=0.8 8.3989 6.1798 4.7291 23.4748Themicrostructure of NiXMnZn1−XFe2O4 ferriteswas examined through SEM analysis and theimageswasprovidedinFigure3.Themicrostructureofthesynthesizedsampleshowsnormalgraingrowth,uniformandhomogeneousdistributionofNi‐Mn‐Znferrites.

Figure3.SEMimagesofNiXMnZn1−XFe2O4,whereSample1(S1)X=0.2;Sample2(S2)X=0.4;Sample3(S3)X=0.6;andSample4(S4)X=0.8

TheaveragegrainsizewascalculatedfromthemicrostructureofthesurfaceintheSEMimage.Theresultsareas follows:S1=0.656μm,S2=1.083μm,S3=1.179μm,andS4=1.0180μm.Grain diameter was determined eight or ten times at random, and the average value wasobtained.ThechangeinthegrainsizecouldbeduetotheincreaseintheNicontent,thatis,thegrainsizeincreasedwithincreasingNicontent.Moreover,theionicradiiofNiincreasedwhentheparticlesizewasincreased.ThegrainsizeincreasedwhenNicontentwassetasX=0.6anddecreased thereafter.Table2 andFigure4 show the changes ingrain sizewith increasingNicontent.

S1 S2

S3 S4


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Table2GrainsizevariationinNiXMnZn1−XFe2O4samples

Composition Grainsize(µm)

Ni0.2MnZn0.8Fe2O4 0.656375

Ni0.4MnZn0.6Fe2O4 1.083

Ni0.6MnZn0.4Fe2O4 1.179

Ni0.8MnZn0.2Fe2O4 1.0180

Figure4.ConcentrationofNiversusgrainsizeBasedontheArrhenius’relation,activationenergywascalculatedusingtheformula:

ρ=ρ0exp(Ea/kT) (6)

whereEaistheactivationenergy,kistheBoltzmannconstant,andρistheresistivityatabsolutetemperature,T.TheresultsareshowninTable3.

Table3VariationsintheCurietemperatureandactivationenergyofNiXMnZn1−XFe2O4samples

No.ofsample

Composition ResistivityΩ‐cminroomtemperature

Curitemperature(K)

ActivationEnergyEaineV

1 Ni0.2MnZn0.8Fe2O4 8.456X106 383 0.5289

2 Ni0.4MnZn0.6Fe2O4 9.163X106 413 0.4128

3 Ni0.6MnZn0.4Fe2O4 1.5295X107 498 0.3986

4 Ni0.8MnZn0.2Fe2O4 1.5691X107 458 0.3954

Figure5showstheplotoftheCurietemperature(Tc)ofthesampleversus1000/T.TheCurietemperature (Tc) is an essential property of ferromagneticmaterials. The lnρ versus 1000/Tcurves of all the samples were of the same characteristics up to a definite temperature. AsshowninTable3andfigure6(a),thevalueofTcincreasedfromsampleS1(x=0.2)toS3(x=0.6)butdecreasedinS4(x=0.8).Figure6(b)showstheactivationenergyslightlydecreasedwithNicontent,andthisresultissimilartothereportbySattaretal.[16].Moreover,theresistivityand

0.6

0.7

0.8

0.9

1

1.1

1.2

1.3

0.1 0.3 0.5 0.7 0.9

Grain size in

μm

Concentration of Ni content


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TcincreasedwithNicontent.TheincreaseintheTccouldbeattributedtothedecreaseintheA–B interaction. As the Ni content increases, the relative number of Fe2+ ions on the A siteincreases,therebyreducingtheA–Binteraction[17].

5 10 15 20 25 30

1

2

3

4

5

6

7

8

Res

isti

vity

cm

(1000/T K)

X=0.2 X=0.4X=0. 6 X=0.8

1000/T K Vs Resistivity

Figure5.1000/TversusresistivityofNiXMnZn1−XFe2O4.

Figure6.(a)ConcentrationversusCurietemperatureand(b)Concentrationversusactivationenergy

The frequency dependence of dielectric constant (έ) for all the sampleswas studied at roomtemperature.Figure7(a)showsthevariationindielectricconstantwithfrequency.Thevalueofέdecreasedcontinuouslywithincreasingfrequency.Thefrequencydependenceofthesamples(Ni–Mn–Zn ferrites) showed a normal dielectric behavior, similar to that describedbyRadhaandRavinder[18].Thisreductionoccursbecausebeyondacertainfrequencyoftheexternallyapplied electric field, the electronic exchange between Fe2+ ↔ Fe+3 ions cannot follow thealternatingfield.Thisbehaviorisingoodagreementwiththeresultofourpreviouswork[19].According toRefs. [20] and [21], the conductionmechanismof ferrites is strongly correlatedwiththeirdielectricbehavior.ThevariationindielectriclosswithfrequencyisshowninFigure7(b).ThedielectriclossdecreasedwhenthefrequencyoftheappliedACelectricfieldislowerthanthehopping frequencyofelectronsbetweenFe+2andFe+3 ionsatneighboringoctahedralsiteswhere theelectrons followthe field leadingtomaximumloss.Athigh frequenciesof theappliedelectricfield,thehoppingfrequencyoftheelectronexchangecannotfollowtheappliedfieldbeyondcertaincritical frequency,and the loss isat theminimum.Themaximumtanδof

360

410

460

510

0 0.2 0.4 0.6 0.8 1

Cur

ie te

mpe

ratu

re


Concentration of Ni content Vs Curie temparature

0.35

0.4

0.45

0.5

0.55

0 0.5 1

Act

ivat

ion

ener

gy e

V


Cocentration of Ni content Vs activation energy in eV


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NixMnZn1−xFe2O4wasobservedat75KHz, and theminimumdielectric loss tangentvaluewasdetectedat10MHzfrequency.Thetanδdecreasedgraduallywithincreasingfrequency.

10 100 1000 10000 100000 1000000

0

200

400

600

800

1000

1200

1400

1600

1800

Die

lelc

tric

con

stan

t/

Frequency in Hz

x=0.2x=0.4x=0.6x=0.8

Frequency Vs Dielectric Constant

200000 400000 600000 800000 10000000.05

0.10

0.15

0.20

0.25

0.30

0.35

0.40

Frequency in Hz

X=0.2X=0.4X=0.6X=0.8

Frequency Vs Dielectric loss

Die

lect

ric

loss

, tan

Figure7(a).Frequencyversusdielectricconstant Figure 7(b): Frequencyversusdielectricloss

The variations in AC resistivity and conductivity are shown in Figure 8 (a) and 8 (b)respectively.TheACresistivityandconductivityofNi–Mn‐Znferriteswerecollectedfrequencyrange of 1 MHz to 10 MHz at room temperature by using an impedance analyzer. The ACresistivitydecreasedwithincreasingfrequency.Bycontrast,theACconductivity(σ)increasedwith increasing frequency for all the samples. Thus, the resistivity and conductivity showedopposite characteristics in response to the frequency. Koops theory and Maxwell–Wangertheory[22–24]explainedthattheACconductivityincreaseswithincreasingfrequency,andthistrend is in agreement with experimental results in this study. The frequency dependence ofresistivitycanbeexplainedby theVerwey’shoppingmechanism[25].At lowfrequencies, thegrainboundariesareactiveandthehoppingactivitiesofferrousandferric(Fe2+&Fe+3)ionsarelow.Asthefrequencyoftheappliedfieldincreases,theconductivegrainsbecomemoreactive,thereby promoting the hopping mechanism between Fe2+ and Fe+3 ions and increasing thehoppingconduction.Theconductivitygraduallyincreasedwithfrequency.

0 200000 400000 600000 800000 10000000

1000000

2000000

3000000

4000000

5000000

6000000

7000000

8000000

Resi

stiv

ity

(-c

m)

Frequency in Hz

X=0.2 X=0.4 X=0.6 X=0.8

Frequency Vs Resistivity

0 200000 400000 600000 800000 1000000

0.0000005

0.0000010

0.0000015

0.0000020

0.0000025

Con

duct

ivit

y

(S/m

)

Frequency in Hz

X=0.2 X=0.4 X=0.6 X=0.8

Frequency Vs Conductivity

Figure8(a).Frequencyversusresistivity Figure 8(b). Frequencyversusconductivity

Figure 9 shows the plot of initial permeability as a function of frequency for the samplessinteredat1100°C.Thevalueofμi increasedwith increasingNi contentbecauseof increasedgrain size and enhanced magnetization [26]. The initial permeability of the sample wasinfluencedbythefrequency.Hence,highinitialpermeabilitycanbeobtainedbyincreasingtheNiconcentration,but the frequencystabilitydecreases.Moreover, thepermeabilitydecreasedrapidly in lowfrequencyregionsandbecomesalmostconstant.Thepermeabilityof ferrites isassociated with two types of mechanisms, namely, spin rotation magnetization inside thedomains and domainwall motion [27–28]. Figure 10 shows the plot of frequency versus Q‐


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factor for Ni–Mn–Zn ferrites. The Q‐factor increased gradually with increasing frequency.Ferrites exhibit high Q‐factor and DC resistivity of the order of 106 Ω‐cm and thus are veryusefulfortransformercoreapplicationsuptofewMHzfrequencies.

10000 100000 1000000 1E7 1E8

50

100

150

200

250

300

Initia

l per

mea

bility

i

Frequency in Hz

X=0.2 X=0.4 X=0.6 X=0.8

Frequency Vs Initial Permeability

Figure9.Frequencyversusinitialpermeability

100 1000 10000 100000 10000000.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

4.0

4.5

5.0

5.5

6.0

6.5

7.0

Qua

lity

fac

tor,

Q

Frequency in Hz

X=0.2 X=0.4 X=0.6 X=0.8

Frequency Vs Quality Factor

Figure10. Frequencyversusqualityfactor

4. CONCLUSIONSIn this study, NiXMnZn1–XFe2O4 ferrites which play an important role in enhancing magnetic,electrical, and dielectric properties was successfully synthesized. Both the bulk and X‐raydensitiesofthesamplesdecreasedwithincreasingNicontent.TheXRDpatternconfirmedthesingle‐phasecubicspinelstructure.Magneticproperties,suchasinitialpermeability,werealsoassessed as a function of frequency. The real part of permeability decreased gradually withincreasingNicontent.Thedecrease in thedielectricconstantwith increasing frequencycouldbe due to the electronic exchange between Fe2+ and Fe3+ ions in octahedral sites, and thisexchangedoesnotfollowthefrequencyoftheappliedACfield.WhenincreasingNicontent,theCurie temperature and DC resistivity increased but the activation energy decreased. These


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experimental results provide a basis for the promising high‐frequency applications of ferritematerials.ACKNOWLEDGEMENT

WearegratefultoBCSIRforgrantingusthepermittocarryoutthisresearchwork.WewouldliketoexpressourgratitudetoDr.Md.ToffazalHossain,ascientistfromBCSIR,forhishelpandcooperation. Finally, we would like to thank all the scientists and staff of Industrial PhysicsDivision,BCSIRLaboratories,Dhakafortheirassistance.

REFERENCES[1] C.Kittel,“IntroductiontoSolidStatePhysics,"7thed.,JohnWileyandSonsInc.,1996.[2] J.Ding,W.MMiao,P.GMcCormick,R.Street,“MechanochemicalsynthesisofultrafineFe

powder”,Appl.Phys.Lett.67(1995)3804.[3] J.Campbell,W.A.Kaczmarck,G.Wang,”Mechanochemicaltransformationofhaematiteto

magnetite”,Nanostruct.Mater.6(1995)735.[4] J.Wang,C. Zeng, Z.Peng,Q.Chen,” Synthesis andmagneticpropertiesof Zn1−XMnXFe2O4

nanoparticles”,PhysicaB349(2004)124.[5] A.H.Morrish, P.E. Clark, “High‐fieldMössbauer study ofmanganese‐zinc ferrites”, Phys.

Rev.B11(1975)278.[6] U.Ghazanfar,S.A.Siddiqi,G.Abbas,“StructuralanalysisoftheMn–Znferritesusing

XRDtechnique”,Mater.Sci.Eng.B118(2005)84.[7] G. Ott, J.Wrba, R. Lucke, “Recent developments ofMn–Zn ferrites for high permeability

Applications”,J.Magn.Magn.Mater.254‐255(2003)535.[8] A. K. Sing, T.C. Goel, R.G. Mendiratta, “Dielectric properties of Mn‐substituted Ni‐Zn

Ferrites”,J.Appl.Phys.,91(2002)6626.[9] G. F.Dionne,R.G.west, “Magnetic andDielectricPropertiesof theSpinel Ferrite System

Nio.65Zno.35Fe2‐xMnx04”,J.Appl.Phys.61(1987)3868.[10] R.Arulmurugan,B.Jeyadevan,G.Vaidyanath,S.Sendhilnathan,”Effectofzincsubstitution

onCo–ZnandMn–Znferritenanoparticlespreparedbyco‐precipitation”,J. Magn.Magn.Mater.288(2005)470.

[11] A.Chatterjee,D.Das,S.K.Pradhan,D.Chakravorty, “Synthesisofnanocrystallinenickel‐zincferritebythesol‐gelmethod”,J.MagnMagn.Mater.127(1993)214.

[12] X. L. Jiao, D. R. Chen, Y. Hu, “Hydrothermal synthesis of nanocrystalline MxZn1−xFe2O4(M=Ni,Mn,Co;x=0.40–0.60)powders”,Mater.Res.Bull.37(2002)1583.

[13] D.J.Fatemi,V.G.Harris,V.M.Browning,J.P.Kirkland,“ProcessingandcationredistributionofMnZnferritesviahigh‐energyballmilling”,J.Appl.Phys.83(1998)6867.

[14] J. Ding, P. G. McCormick, R. Street, “Formation of spinel Mn‐ferrite during mechanicalAlloying”,J.Magn.Magn.Mater.171(1997)309.

[15] V. Sepelak, A. Buchal, K. Tkácová, K. D. Becker, “Nanocrystalline Structure of theMetastableBall‐MilledInverseSpinel‐Ferrites”,Mater.Sci.Forum278(1998)862.

[16] A.A.Sattar,H.M.El‐Sayed,W.R.Agami,A.A.Ghani, “MagneticPropertiesandElectricalResistivity of Zr4+ Substituted Li‐Zn Ferrite”, American Journal of Applied Sciences,4,Issue2,Pages89‐93,2007.

[17] R. C. Kambale, P. A . Shaikh, C. H. Bhosale, K. Y. Rajpure and Y. D. Kolekar, “Dielectricpropertiesandcomplex impedancespectroscopystudiesofmixedNi‐Co ferrites”,SmartMater.Struct,18(2009)0850149(6pp)

[18] D.Ravinder,K.VijayKumer,“DielectricbehaviouroferbiumsubstitutedMn‐Znferrites”.BulletinofMaterialScience,24,Issue5,October2001,pp.505‐509.


24

[19] M.Shahjahan,N.A.Ahmed,S.N.Rhaman,S.Islam,N.Khatun,M.S.Hossain“StructuralandElectrical Characterization of Li‐Zn Ferrites”. International Journal of InnovativeTechnologyandExploringEngineeringexploringengineering(Ijitee),3, Issue‐8, January2014.

[20] K. Iwauchi “Dielectric properties of fine particles of Fe3O4 and some ferrites” JapaneseJournalofAppliedPhysics,10,1971,pp.1520‐1528.

[21] N. Rezlescu, E. Rezlescu, “Dielectric Properties of Copper Containing Ferrites,” PhysicaStatusSolidi(A),23,No.2,1974,pp.575‐582.

[22] Maxwell,JamesClerk,“ATreatiseonElectricityandMagnetism”Oxford:ClarendonPress,Publicationdate1873.

[23] K.W.Wagner,“ZurTheoriederunvollkommenenDielektrika”AnnPhysicsLeipzig,40,(1913)817.

[24] C. G. Koop’s,“ On the dispersion of resistivity and dielectric constant of somesemiconductorsataudiofrequencies”,Phys.Rev.83(1951)121‐126.

[25]Rekha Rania, J. K. Juneja, K. K. Raina, Chandra Prakash, “Studies of the dielectric andferroelectric properties of PZT: NZF magnetoelectric composites Ceramic Processing”Research.13,(2012)76.

[26]N.Rezlescu,E,Rezlescu,P.D.Popa,M.L.Craus,L.Rezlescu,“Copperionsinfluenceonthephysical properties of a magnesium‐zinc ferrite”, Journal of Magnetism and MagneticMaterials,182,Issuse1‐2(1998)pp199‐206.

[27]M.M.Rahman,P.K.Halder,F.Ahmed,T.Hossain,M.Rahaman,“EffectofCa‐substitutionontheMagneticandDielectricPropertiesofMn‐ZnFerrites”J.Sci.Res.4(2),(2012)297‐306.

[28] Md. Mamun‐Or‐Rashid, Humayun Kabir, Mashudur Rahaman, Md. Abdul Gafur, A.T.M.K.Jamil, Syed Jamal Ahmed , Abdulla Al Noman, Farid Ahmed, “Investigation of theStructural,DielectricandElectricalpropertiesofZn‐substitutedLi‐Niferrite”IOSRJournalofAppliedPhysics(IOSR‐JAP)E‐ISSN:2278‐4861.7, Issue5Ver. I (Sep. ‐Oct.2015),PP76‐83

[29] Zhilun Gui, Ji. Zhou, Longtu Li, Xiaohui Wang, Zhilun Gui, “Effect of Copper On theElectromagnetic Properties of Mg‐Zn‐Cu Ferrites Prepared by Sol‐gel Auto CombustionMethod.”MaterialsScienceandEngineering:B86,Issue1(2001)pp64‐69.

synthesis and characterization of structural, magnetic and ... no. 1 2018...zn ferrites play a vital...

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