research article microwave absorption properties of double-layer radar absorbing … · 2019. 7....

Research ArticleMicrowave Absorption Properties of Double-LayerRADAR Absorbing Materials Based on Doped BariumHexaferriteTiO2Conducting Carbon Black

Sukanta Das1 G C Nayak1 S K Sahu2 P C Routray2 A K Roy2 and H Baskey3

1 Department of Applied Chemistry Indian School of Mines Dhanbad 826004 India2 Integrated Test Range (ITR) Chandipur 756025 India3 DMSRDE Kanpur 208013 India

Correspondence should be addressed to G C Nayak ganeshnayak2006gmailcom

Received 18 May 2014 Revised 14 August 2014 Accepted 7 September 2014 Published 17 September 2014

Academic Editor Mariatti Jaafar

Copyright copy 2014 Sukanta Das et al This is an open access article distributed under the Creative Commons Attribution Licensewhich permits unrestricted use distribution and reproduction in any medium provided the original work is properly cited

In this report we demonstrate microwave absorption properties of barium hexaferrite doped barium hexaferrite titanium dioxideand conducting carbon black based RADAR absorbing material for stealth application Double-layer absorbers are prepared witha top layer consisting of 30 hexaferrite and 10 titanium dioxide while the bottom layer composed of 30 hexaferrite and 10conducting carbon black embedded in chloroprene matrix The top and bottom layers are prepared as impedance matching layerand conducting layer respectively with a total thickness of 2mm Microwave absorption properties of all the composites wereanalyzed in X-band region Maximum reflection loss of minus32 dB at 1064GHz was observed for barium hexaferrite based double-layer absorber whereas for doped barium hexaferrite based absorber the reflection loss was found to be minus2956 dB at 117 GHz Aconsistence reflection loss value (gtminus24 dB) was observed for doped barium hexaferrite based RADAR absorbing materials withinthe entire bandwidth

1 Introduction

In the recent years X-band RADAR application increasesin military sector due to its high precision target detec-tion capability Keeping it in view microwave technologyadvancement is forced to focus on the development of effi-cient RADAR absorbing materials (RAMs) for applicationsin the field of stealth technology [1] and electromagnetic(EM) shielding Therefore there is a demand for effectivemicrowave absorbing materials for wideband applicationsRADAR wave in the form of EM energy can be completely orpartially absorbed and dissipated into the absorbingmaterialsthrough magnetic and dielectric losses The phenomenon ofthe absorption is prominent if characteristic impedance ofthe free space is equal to the characteristic impedance ofthe absorber Efficient RAMs can be prepared with materialswhich allows EMwave to penetrate easily and attenuatewholeof the electromagnetic energy within itself [2] Ferrites basedRAMs show interesting behavior in X-band frequency range

and have been used in the form of sheets films paintsand ceramic tiles Hexagonal barium hexaferrite and dopedbarium hexaferrite are suitable candidates to be used todevelop composite RAMs due to their good permittivity andpermeability value within X-band region Gairola et al [3]reported a maximum reflection loss of minus147 dB for 2mmthick single-layered RAMs based on barium hexaferrite andCo Mn and Ti substituted barium hexaferrite Qiu et al[4] reported a nanocomposite multilayer absorber film usingbarium hexaferrite (BaFe

12O19) and titanium dioxide (TiO

2)

with a maximum loss of minus40 dB due to the dielectric effect oftitanium dioxide Lopes et al [5] studiedmicrowave absorberbased on nonwoven polyacrylonitrile fabric and conductingcarbon black (CCB) and reported a reflection loss of minus22 dBin X-band region However all the reported electromagneticabsorber showed narrowband absorption which is a majordrawback in RAMs development

In this work Fe within barium hexaferrite was substitutedwith cobalt titanium and manganese which helped in

Hindawi Publishing CorporationJournal of EngineeringVolume 2014 Article ID 468313 5 pageshttpdxdoiorg1011552014468313

2 Journal of Engineering

tailoring magnetic properties Both barium hexaferrite anddoped barium hexaferrite along with conducting carbonblack (CCB) and titanium dioxide (TiO

2) were utilized

to develop double-layer RADAR absorbing materials withwideband absorption capability

2 Experiments

21 Preparation of Barium Hexaferrite (BaHF) A typicalsintering method was followed for the synthesis of bariumhexaferrite (BaFe

12O19) from barium carbonate (BaCO

3) and

iron oxide (Fe2O3) as reported by Gumaste et al [6] Both

the compounds were mixed in a ball mill for 6 hours instoichiometric ratio (1 6) The homogeneous mixture wasthen dried at 100∘C for 24 hours to remove moisture Afterthat calcination of the sample was carried out at 600∘Cfor two hours and sintered at 1200∘C for one hour Thepowder sample was collected at room temperature for furthercharacterization and processing

22 Preparation of Doped Barium Hexaferrite (CoTiMn-BaHF) Doped barium hexaferrite (BaFe

10Co08Ti08Mn04

O19) was prepared by ldquomixed oxiderdquo approach as reported

by Lima et al [7] In this synthesis process substitution ofFe3+ sites was carried out to make the materials magneticallysoft in nature All the individual components cobalt oxide(CoO) titanium oxide (TiO

2) manganese oxide (MnO)

barium carbonate (BaCO3) and iron oxide (Fe

2O3) were

mixed together as their stoichiometric arrangements in a ballmill Then the sample was dried by putting it into oven at100∘C for 24 hoursThe powder sample was calcined at 600∘Cfor 2 hours and sintered at 1200∘C for 1 hour The powdersample of doped barium hexaferrite was collected for furthercharacterization and processing

23 Preparation of Double-Layer RAMs Two RAMs (RAM-I and RAM-II) were prepared in chloroprene rubber (CR)matrix supplied by Dupont BaHF based double-layer RAMswere made by two-step process The composite RAMs wereprepared by following the procedure reported by Peng etal [8] In the first step top layer of RAM-I was preparedby mixing 30 (ww) BaHF and 10 (ww) TiO

2with CR

matrix in an open two-roll mixture The other processingadditives added to the mixture were stearic acid (05 phr)CBS (06 phr) TMTD (02 phr) ZnO (3 phr) MgO (2 phr)and sulfur (15 phr) After completion of mixing the materialwas pressed at room temperature by keeping it in a 1mmthick mold to maintain its thickness The 1mm thick bottomlayer was prepared by mixing 30 (ww) BaHF and 10(ww) CCB with CR matrix in two-roll mixture along withother additives and pressed at room temperature to get 1mmthick sheet Now both the layers were placed into a 2mmthick mold and the mold was kept in between two hot platesTemperature of the hot plates increases up to 150∘C and 2-bar pressure applied for 15minThen temperature of themoldreduced down to room temperature and double-layer RAM-I was taken out of mold RAM-II was prepared by using

same methodology as RAM-I and only BaHF was replacedby CoTiMn-BaHF

3 Characterizations

The particle size and morphology of the BaHF CoTiMn-BaHF CCB and TiO

2were measured using field emission

scanning electron microscope (FESEM) at an acceleratingvoltage of 5 kV XRD was carried out for both BaHF andCoTiMn-BaHF using Rigaku Ultima III with cobalt source(120582= 178896 A)The complex permittivity and permeability ofthe composite RAMsweremeasured using anAgilent E8362Bvector network analyzer (VNA) in the frequency rangeof 8ndash12GHz Reflection loss properties of the compositeRAMs were measured using Agilent E8364B in the X-bandfrequency range (8ndash12GHz)

4 Results and Discussion

41 Morphological Study FESEM images of BaHF CoTiMn-BaHF CCB and TiO

2samples are given in Figures 1(a)ndash1(d)

It was observed that particle size of doped BaHF is smallerthan undoped BaHF Figure 1(a) shows the BaHF particleswith an average diameter of 500 nm whereas the averageparticle size of CoTiMn-BaHF was found to be 300 nm TheCCB particles appeared to be spherical in nature and withan average diameter of 30 nm (Figure 1(c)) Figure 1(d) showsthe microstructure of TiO

2 which appeared as flakes

42 X-Ray Diffraction XRD diffractograms of BaHF anddoped barium hexaferrite (CoTiMn-BaHF) are shown inFigure 2 Most of the peak patterns of CoTiMn-BaHF arethe same as pure BaHF The crystal planes are identified forboth BaHF and CoTiMn-BaHF and indexed using JCPDSnumber 43-0002 ((101) (102) (006) (110) (107) (114) (203)(205) (206) (217) (2011) and (220)) The XRD patternshows that Mn+2 Co+2 and Ti+4 ion were rearranged withinthe hexagonal magnetoplumbite structure to maintain theformation of single phase hexagonal ferrite entityThe averagecrystallite diameter (ACD) of the BaHF and CoTiMn-BaHFparticles was measured as 42 nm and 32 nm from the majordiffraction peak (114) using thewell-known Scherrer formulaDue to substitution it can be seen that peak height decreasedwhich can be attributed to the doaping effcet on crystallinity

43 Magnetic Properties A vibrating sample magnetometer(VSM) was used tomeasure themagnetic properties of BaHFand CoTiMn-BaHF The resulting hysteresis loops providedthe relationship between magnetization (119872) and appliedfield (119867) at room temperature The parameters extractedfrom the hysteresis loops are saturation magnetization (Ms)remanence (Mr) and coercivity (Hc) Figure 3 shows thehysteresis loops for the BaHF and CoTiMn-BaHF Becauseof high value of Hc 4194Oe for BaHF the material is ahard magnetic material [7] From the plot it can be seenthat Hc value for CoTiMn-BaHF is 1496Oe Hysteresisloops show reduction in coercive force (Hc) for CoTiMn-BaHF classifying the material as soft magnetic material The

Journal of Engineering 3

(a) (b)

(c) (d)

Figure 1 Surface morphology of (a) BaHF (b) CoTiMn-BaHF (c) CCB and (d) TiO2particles

10 20 30 40 50 60 70 80

0

200

400

600

800

1000

Inte

nsity

(au

)

(101

)(102

)(006

)

(110

)(107

)

(203

)(114

)

(204

)(205

)

(206

)

(217

)(2011

)

(220

)

BaHFCoTiMn-BaHF

(201

)

Angle (2120579)

Figure 2 XRD of BaHF and CoTiMn-BaHF

reduction of particle size of CoTiMn-BaHF may be the mainreason of low coercivity The saturation magnetization (Ms)value for BaHF and CoTiMn-BaHF is 5389 emugm andremanence (Mr) value is 2962 emugm

44 Permittivity and Permeability Study The complex per-mittivity and permeability study represents the magnetic anddielectric properties of themicrowave absorberThe real parts

60

40

20

0

minus20

minus40

minus60

Mag

netiz

atio

n (e

mu

gm)

minus20000 minus10000 0 10000 20000

Applied magnetic field H (Oe)

BaHFCoTiMn-BaHF

Figure 3 Hysteresis plot of BaHF and CoTiMn-BaHF

of permittivity and permeability (1205761015840 and 1205831015840) represent themeasure of energy storage capability into the system Theimaginary parts of permittivity and permeability (12057610158401015840 and120583

10158401015840) represent the measure of energy loss capability of theabsorber The real and imaginary component of permeabilityfor multilayer RAM-I and RAM-II were plotted over therange of 8ndash12GHz and shown in Figure 4(a) The plot showsreal and imaginary component of permeability for both


Real

and

imag

inar

y pa

rt o

f per

mea

bilit

y

Frequency (GHz)

RAM-I RAM-IRAM-II RAM-II

120583998400 120583998400998400

12

10

08

06

04

02

00

8 9 10 11 12 13

(a)

Frequency (GHz)8 9 10 11 12 13

120576998400 120576998400998400

45

40

35

30

25

20

15

10

05

00


Real

and

imag

inar

y pa

rt o

f per

mitt

ivity

(b)

Figure 4 (a) Real and imaginary part of permeability for RAMs (I and II) (b) real and imaginary part of permittivity for RAMs (I and II)

RAM-I and RAM-II which are nearly constant within 9ndash12GHz segment The plot shows that imaginary part ofpermiability is small and possessed a peak at 862GHz whichconfirmed the existence of slightly greater magnetic lossmainly because of domain-wall displacement in themagneticcomponents Figure 4(b) shows the complex permittivityspectra of the RAM-I and RAM-IIThe values of both the realand imaginary parts (1205761015840 and 12057610158401015840) of permittivity do not changewithin the entire frequency range of 8ndash12GHzThe dielectricloss may occur due to intrinsic electrical dipole momentwithin double-layer RAMs In addition to this dielectriclosses can also occur in presence of electromagnetic field dueto polarization relaxation

45 Microwave Absorbing Properties An ideal microwaveabsorber should meet impedance matching (119885in = 119885o) con-dition [9] Hexaferrites materials have matching frequencydue to magnetic resonance within the X-band region Theabsorption condition satisfies where reflection loss valueis maximum and condition ideally possible to meet whenthe materials complex permittivity and permeability valuesare equal When intrinsic impedance is greater than unity|120583

119903| gt |120576

119903| maximum attenuation can be achieved if thick-

ness of RAMs is equal to half of wave length (1205822) If intrinsicimpedance of the material is less than unity |120583

119903| lt |120576

119903|

then quarter wave length (1205824) is sufficient to achieve max-imum attenuation For hexaferrite based materials intrinsicimpedance value is less than unity in X-band frequencyrange so maximum attenuation can be achieved if thicknessof RAMs will be equal to 1205824 or odd multiple of 1205824 [10ndash13] From Figures 5(a) and 5(b) variation of attenuationproperty with frequency for BaHF and CoTiMn-BaHF baseddouble-layer composite RAMs can be seen The BaHF based

composite (RAM-I) exhibited a reflection loss of minus32 dB at1064GHz (Figure 5(a)) whereas by doped bariumhexaferritebased absorber (RAM-II) it exhibited a maximum reflectionloss of minus2956 dB at 117 GHz It was also observed that BaHFbased composite did not possess a consistence reflectionloss below minus20 dB in the whole range of analysis because ofits ferromagnetic resonance at 1064GHz However dopedBaHF based double-layer RAMs showed wide bandwidth ofabsorption in X-band frequency range and the resonancefrequency also shifted to 117 GHz The better microwaveabsorption properties of doped barium hexaferrite basedRAMs can be attributed to reduction in particle size andcoercive force (Hc) as compared to barium hexaferrite(BaHF) based absorber Figure 5(b) shows the variation oftransmission loss versus frequency for RAM-I and RAM-II As expected transmission loss curves were completelyreversed of reflection loss curves

5 Conclusion

Barium hexaferrite with narrow shape and size distribu-tion was successfully synthesized using topotactic sinter-ing method Doped barium hexaferrite (BaFe

10Co08Ti08

Mn04O19) was prepared by ldquomixed oxiderdquo approach Double-

layered RAMs were prepared successfully with both BaHFand doped BaHF embedded in chloroprene rubber Themaximum reflection loss values were observed as minus32 dB at1064GHz for BaHFTiO

2CCB based composite RAMsThe

maximum reflection loss value for doped-BaHFTiO2CCB

based absorber was found to be minus2956 dB at 117 GHzHowever doped BaHF based RAMs showed consistencemicrowave absorption which is reflected in reflection lossvalues in the whole X-band region



minus16

minus18

minus20

minus22

minus24

minus26

minus28

minus30

minus32

minus34

Refle

ctio

n lo

ss (d

B)

RAM-IRAM-II

(a)

0

minus2

minus4

minus6

minus8

minus10

minus12

minus14


RAM-IRAM-II

Tran

smiss

ion

loss

(dB)

(b)

Figure 5 (a) Reflection loss (dB) versus frequency (GHz) (b) Transmission loss (dB) versus frequency (GHz)

Conflict of Interests

The authors declare that there is no conflict of interestsregarding the publication of this paper

Acknowledgment

The authors are grateful for the support from Director ofIntegrated Test Range (ITR) Defence Research DevelopmentOrganization (DRDO) Chandipur India

References

[1] A Ohlan K Singh A Chandra and S K Dhawan ldquoMicrowaveabsorption behavior of core-shell structured poly (34-ethylenedioxy thiophene)mdashbarium ferrite nanocompositesrdquoACS Applied Materials and Interfaces vol 2 no 3 pp 927ndash9332010

[2] R Sharma R C Agarwala and V Agarwala ldquoDevelopmentof radar absorbing nano crystals under thermal irradiationrdquoJournal of Nano Research no 2 pp 91ndash104 2008

[3] S PGairola VVermaA Singh L P Purohit andRKKotnalaldquoModified composition of barium ferrite to act as a microwaveabsorber in X-band frequenciesrdquo Solid State Communicationsvol 150 no 3-4 pp 147ndash151 2010

[4] J Qiu Y Wang and M Gu ldquoMicrowave absorption propertiesof substituted BaFe

12O19TiO2nanocomposite multilayer filmrdquo

Journal of Materials Science vol 42 no 1 pp 166ndash169 2007[5] C M A Lopes G G Peixoto and M C Rezende ldquoMicrowave

absorption effectiveness of non woven support impregnatedwith carbon blackrdquo in Proceedings of the SMBOIEEE MTT-SInternationalMicrowave andOptoelectronics Conference (IMOCrsquo03) pp 771ndash774 September 2003

[6] J L Gumaste B B Nayak R K Galgali and B C MohantyldquoBarium hexaferrite magnet by topotactic reaction methodrdquoJournal of Materials Science vol 23 no 9 pp 3125ndash3128 1988

[7] R D C LimaM S PinhoM L Gregori R C R Nunes and TOgasawara ldquoEffect of double substitutedm-bariumhexaferritesonmicrowave absorption propertiesrdquoMaterials Science-Polandvol 22 no 3 pp 245ndash252 2004

[8] C-H Peng C-C Hwang J Wan J-S Tsai and S-Y ChenldquoMicrowave-absorbing characteristics for the composites ofthermal-plastic polyurethane (TPU)-bondedNiZn-ferrites pre-pared by combustion synthesis methodrdquoMaterials Science andEngineering B Solid-State Materials for Advanced Technologyvol 117 no 1 pp 27ndash36 2005

[9] S H Hosseini and A Asadina ldquoSynthesis characterizationand microwave-absorbing properties of polypyrroleMnFe

2O4

nanacompositerdquo Journal of Nanomaterials vol 2012 Article ID198973 6 pages 2012

[10] A R Bueno M L Gregori and M C S Obrega ldquoMicrowaveabsorbing of Ni

050minus119909Zn050minus119909

Mn2119909Fe2O4(Me=Cu Mn Mg)

ferrite wax composite in X-band frequenciesrdquo Journal of Mag-netism and Magnetic Materials vol 320 no 6 pp 864ndash8702008

[11] H S Al-Jumaili K T Rasoul and S N Al-Rashed ldquoTheeffect of Mn and Ti substituted barium hexaferrite on theelectromagnetic microwave absorber in the X-band rangerdquoJournal of Al-Anbar University of Pure Science vol 1 no 2 pp62ndash74 2007

[12] H-M Xiao X-M Liu and S-Y Fu ldquoSynthesis magneticand microwave absorbing properties of core-shell structuredMnFe

2O4TiO2nanocompositesrdquoComposites Science and Tech-

nology vol 66 no 13 pp 2003ndash2008 2006[13] L D C FolguerasM A Alves andM C Rezende ldquoMicrowave

absorbing paints and sheets based on carbonyl iron andpolyani-line Measurement and simulation of their propertiesrdquo Journalof Aerospace Technology and Management vol 2 no 1 pp 63ndash70 2010

International Journal of

AerospaceEngineeringHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

RoboticsJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014


Active and Passive Electronic Components

Control Scienceand Engineering

Journal of



RotatingMachinery


Hindawi Publishing Corporation httpwwwhindawicom

Journal ofEngineeringVolume 2014

Submit your manuscripts athttpwwwhindawicom

VLSI Design



Shock and Vibration


Civil EngineeringAdvances in

Acoustics and VibrationAdvances in



Electrical and Computer Engineering

Journal of

Advances inOptoElectronics


Volume 2014

The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014

SensorsJournal of


Modelling amp Simulation in EngineeringHindawi Publishing Corporation httpwwwhindawicom Volume 2014


Chemical EngineeringInternational Journal of Antennas and

Propagation




Navigation and Observation



DistributedSensor Networks



tailoring magnetic properties Both barium hexaferrite anddoped barium hexaferrite along with conducting carbonblack (CCB) and titanium dioxide (TiO

2) were utilized

to develop double-layer RADAR absorbing materials withwideband absorption capability

2 Experiments

21 Preparation of Barium Hexaferrite (BaHF) A typicalsintering method was followed for the synthesis of bariumhexaferrite (BaFe

12O19) from barium carbonate (BaCO

3) and

iron oxide (Fe2O3) as reported by Gumaste et al [6] Both

the compounds were mixed in a ball mill for 6 hours instoichiometric ratio (1 6) The homogeneous mixture wasthen dried at 100∘C for 24 hours to remove moisture Afterthat calcination of the sample was carried out at 600∘Cfor two hours and sintered at 1200∘C for one hour Thepowder sample was collected at room temperature for furthercharacterization and processing

22 Preparation of Doped Barium Hexaferrite (CoTiMn-BaHF) Doped barium hexaferrite (BaFe

10Co08Ti08Mn04

O19) was prepared by ldquomixed oxiderdquo approach as reported

by Lima et al [7] In this synthesis process substitution ofFe3+ sites was carried out to make the materials magneticallysoft in nature All the individual components cobalt oxide(CoO) titanium oxide (TiO

2) manganese oxide (MnO)

barium carbonate (BaCO3) and iron oxide (Fe

2O3) were

mixed together as their stoichiometric arrangements in a ballmill Then the sample was dried by putting it into oven at100∘C for 24 hoursThe powder sample was calcined at 600∘Cfor 2 hours and sintered at 1200∘C for 1 hour The powdersample of doped barium hexaferrite was collected for furthercharacterization and processing

23 Preparation of Double-Layer RAMs Two RAMs (RAM-I and RAM-II) were prepared in chloroprene rubber (CR)matrix supplied by Dupont BaHF based double-layer RAMswere made by two-step process The composite RAMs wereprepared by following the procedure reported by Peng etal [8] In the first step top layer of RAM-I was preparedby mixing 30 (ww) BaHF and 10 (ww) TiO

2with CR

matrix in an open two-roll mixture The other processingadditives added to the mixture were stearic acid (05 phr)CBS (06 phr) TMTD (02 phr) ZnO (3 phr) MgO (2 phr)and sulfur (15 phr) After completion of mixing the materialwas pressed at room temperature by keeping it in a 1mmthick mold to maintain its thickness The 1mm thick bottomlayer was prepared by mixing 30 (ww) BaHF and 10(ww) CCB with CR matrix in two-roll mixture along withother additives and pressed at room temperature to get 1mmthick sheet Now both the layers were placed into a 2mmthick mold and the mold was kept in between two hot platesTemperature of the hot plates increases up to 150∘C and 2-bar pressure applied for 15minThen temperature of themoldreduced down to room temperature and double-layer RAM-I was taken out of mold RAM-II was prepared by using

same methodology as RAM-I and only BaHF was replacedby CoTiMn-BaHF

3 Characterizations

The particle size and morphology of the BaHF CoTiMn-BaHF CCB and TiO

2were measured using field emission

scanning electron microscope (FESEM) at an acceleratingvoltage of 5 kV XRD was carried out for both BaHF andCoTiMn-BaHF using Rigaku Ultima III with cobalt source(120582= 178896 A)The complex permittivity and permeability ofthe composite RAMsweremeasured using anAgilent E8362Bvector network analyzer (VNA) in the frequency rangeof 8ndash12GHz Reflection loss properties of the compositeRAMs were measured using Agilent E8364B in the X-bandfrequency range (8ndash12GHz)

4 Results and Discussion

41 Morphological Study FESEM images of BaHF CoTiMn-BaHF CCB and TiO

2samples are given in Figures 1(a)ndash1(d)

It was observed that particle size of doped BaHF is smallerthan undoped BaHF Figure 1(a) shows the BaHF particleswith an average diameter of 500 nm whereas the averageparticle size of CoTiMn-BaHF was found to be 300 nm TheCCB particles appeared to be spherical in nature and withan average diameter of 30 nm (Figure 1(c)) Figure 1(d) showsthe microstructure of TiO

2 which appeared as flakes

42 X-Ray Diffraction XRD diffractograms of BaHF anddoped barium hexaferrite (CoTiMn-BaHF) are shown inFigure 2 Most of the peak patterns of CoTiMn-BaHF arethe same as pure BaHF The crystal planes are identified forboth BaHF and CoTiMn-BaHF and indexed using JCPDSnumber 43-0002 ((101) (102) (006) (110) (107) (114) (203)(205) (206) (217) (2011) and (220)) The XRD patternshows that Mn+2 Co+2 and Ti+4 ion were rearranged withinthe hexagonal magnetoplumbite structure to maintain theformation of single phase hexagonal ferrite entityThe averagecrystallite diameter (ACD) of the BaHF and CoTiMn-BaHFparticles was measured as 42 nm and 32 nm from the majordiffraction peak (114) using thewell-known Scherrer formulaDue to substitution it can be seen that peak height decreasedwhich can be attributed to the doaping effcet on crystallinity

43 Magnetic Properties A vibrating sample magnetometer(VSM) was used tomeasure themagnetic properties of BaHFand CoTiMn-BaHF The resulting hysteresis loops providedthe relationship between magnetization (119872) and appliedfield (119867) at room temperature The parameters extractedfrom the hysteresis loops are saturation magnetization (Ms)remanence (Mr) and coercivity (Hc) Figure 3 shows thehysteresis loops for the BaHF and CoTiMn-BaHF Becauseof high value of Hc 4194Oe for BaHF the material is ahard magnetic material [7] From the plot it can be seenthat Hc value for CoTiMn-BaHF is 1496Oe Hysteresisloops show reduction in coercive force (Hc) for CoTiMn-BaHF classifying the material as soft magnetic material The


(a) (b)

(c) (d)


10 20 30 40 50 60 70 80

0

200

400

600

800

1000

Inte

nsity

(au

)

(101

)(102

)(006

)

(110

)(107

)

(203

)(114

)

(204

)(205

)

(206

)

(217

)(2011

)

(220

)

BaHFCoTiMn-BaHF

(201

)

Angle (2120579)




60

40

20

0

minus20

minus40

minus60

Mag

netiz

atio

n (e

mu

gm)

minus20000 minus10000 0 10000 20000


BaHFCoTiMn-BaHF





Real

and

imag

inar

y pa

rt o

f per

mea

bilit

y

Frequency (GHz)


120583998400 120583998400998400

12

10

08

06

04

02

00

8 9 10 11 12 13

(a)


120576998400 120576998400998400

45

40

35

30

25

20

15

10

05

00


Real

and

imag

inar

y pa

rt o

f per

mitt

ivity

(b)




119903| gt |120576



119903| lt |120576

119903|



5 Conclusion


10Co08Ti08








minus16

minus18

minus20

minus22

minus24

minus26

minus28

minus30

minus32

minus34

Refle

ctio

n lo

ss (d

B)

RAM-IRAM-II

(a)

0

minus2

minus4

minus6

minus8

minus10

minus12

minus14


RAM-IRAM-II

Tran

smiss

ion

loss

(dB)

(b)




Acknowledgment


References












2O4













RoboticsJournal of





Journal of



RotatingMachinery





VLSI Design



Shock and Vibration







Journal of



Volume 2014


SensorsJournal of





Propagation










(a) (b)

(c) (d)


10 20 30 40 50 60 70 80

0

200

400

600

800

1000

Inte

nsity

(au

)

(101

)(102

)(006

)

(110

)(107

)

(203

)(114

)

(204

)(205

)

(206

)

(217

)(2011

)

(220

)

BaHFCoTiMn-BaHF

(201

)

Angle (2120579)




60

40

20

0

minus20

minus40

minus60

Mag

netiz

atio

n (e

mu

gm)

minus20000 minus10000 0 10000 20000


BaHFCoTiMn-BaHF





Real

and

imag

inar

y pa

rt o

f per

mea

bilit

y

Frequency (GHz)


120583998400 120583998400998400

12

10

08

06

04

02

00

8 9 10 11 12 13

(a)


120576998400 120576998400998400

45

40

35

30

25

20

15

10

05

00


Real

and

imag

inar

y pa

rt o

f per

mitt

ivity

(b)




119903| gt |120576



119903| lt |120576

119903|



5 Conclusion


10Co08Ti08








minus16

minus18

minus20

minus22

minus24

minus26

minus28

minus30

minus32

minus34

Refle

ctio

n lo

ss (d

B)

RAM-IRAM-II

(a)

0

minus2

minus4

minus6

minus8

minus10

minus12

minus14


RAM-IRAM-II

Tran

smiss

ion

loss

(dB)

(b)




Acknowledgment


References












2O4













RoboticsJournal of





Journal of



RotatingMachinery





VLSI Design



Shock and Vibration







Journal of



Volume 2014


SensorsJournal of





Propagation










Real

and

imag

inar

y pa

rt o

f per

mea

bilit

y

Frequency (GHz)


120583998400 120583998400998400

12

10

08

06

04

02

00

8 9 10 11 12 13

(a)


120576998400 120576998400998400

45

40

35

30

25

20

15

10

05

00


Real

and

imag

inar

y pa

rt o

f per

mitt

ivity

(b)




119903| gt |120576



119903| lt |120576

119903|



5 Conclusion


10Co08Ti08








minus16

minus18

minus20

minus22

minus24

minus26

minus28

minus30

minus32

minus34

Refle

ctio

n lo

ss (d

B)

RAM-IRAM-II

(a)

0

minus2

minus4

minus6

minus8

minus10

minus12

minus14


RAM-IRAM-II

Tran

smiss

ion

loss

(dB)

(b)




Acknowledgment


References












2O4













RoboticsJournal of





Journal of



RotatingMachinery





VLSI Design



Shock and Vibration







Journal of



Volume 2014


SensorsJournal of





Propagation











minus16

minus18

minus20

minus22

minus24

minus26

minus28

minus30

minus32

minus34

Refle

ctio

n lo

ss (d

B)

RAM-IRAM-II

(a)

0

minus2

minus4

minus6

minus8

minus10

minus12

minus14


RAM-IRAM-II

Tran

smiss

ion

loss

(dB)

(b)




Acknowledgment


References












2O4













RoboticsJournal of





Journal of



RotatingMachinery





VLSI Design



Shock and Vibration







Journal of



Volume 2014


SensorsJournal of





Propagation











RoboticsJournal of





Journal of



RotatingMachinery





VLSI Design



Shock and Vibration







Journal of



Volume 2014


SensorsJournal of





Propagation









research article microwave absorption properties of double-layer radar absorbing … · 2019. 7....

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