Research Article Structural, Electrical, and Ethanol-Sensing …downloads.hindawi.com/journals/amse/2014/685715.pdf · it was also found that the LaMg 0.1 Fe 0.9 O 3 based sensor

Research ArticleStructural Electrical and Ethanol-Sensing Properties ofLa1minus119909

Nd119909

FeO3

Nanoparticles

Nguyen Thi Thuy1 Dang Le Minh2 Ho Truong Giang3 and Nguyen Ngoc Toan3

1 Physics Department Hue Universityrsquos College of Education Hue Vietnam2 Faculty of Physics Hanoi University of Science VNU Hanoi Vietnam3 Institute of Material Science Institute of Technology and Science Hanoi Vietnam

Correspondence should be addressed to NguyenThiThuy nguyenthithuy0206gmailcom

Received 21 March 2014 Accepted 23 June 2014 Published 18 August 2014

Academic Editor Markku Leskela

Copyright copy 2014 NguyenThiThuy et al This is an open access article distributed under the Creative Commons AttributionLicense which permits unrestricted use distribution and reproduction in any medium provided the original work is properlycited

The nanocrystalline La1minus119909

Nd119909FeO3 (0 le 119909 le 10) powders with orthorhombic perovskite phase were prepared by sol-gel

method The average crystallite sizes of La1minus119909

Nd119909FeO3 powders are about 20 nm The resistance and gas-sensing properties of

the La1minus119909

Nd119909FeO3 based sensors were investigated in the temperature range from 160 to 300∘C The results demonstrated that the

resistance and response of the perovskite thick films changed with the increase of Nd content

1 Introduction

There has been much interest in perovskite structuredcompounds (of general formula ABO

3) because of their

catalytic activity colossal magnetoresistance effectsthermoelectric effects gas-sensing properties and so forth[1ndash8] Specially perovskite oxides with AFeO

3structure (A

rare earth) have shown the good gas-sensing properties suchas LaFeO

3 La1minus119909

Pb119909FeO3 LaMg

119909Fe1minus119909

O3 La07Sr03FeO3

and SmFe1minus119909

Ni119909O3 Among the modified perovskites

La068

Pb032

FeO3

showed the best ethanol gas-sensingcharacteristics its response to 100 ppm ethanol was morethan 80 in the temperature range from 140 to 240∘Cit was also found that the LaMg

01Fe09O3based sensor

had the best response and selectivity to ethanol gas theresponse to 500 ppm ethanol is 128 at 220∘C or the highestresponse to 500 ppm ethanol gas reaches 578 at 260∘C forSmFe095

Ni005

O3sensor and so forth [9ndash12] Numerous

perovskites show p-type semiconductor properties in airOxygen adsorption enhances the conductivity of thesematerials on account of the increased concentration ofholes which are the main charge carrier species in p-typesemiconductors Furthermore their resistance increasesby applying reducing gases such as ethanol Interaction

between the reducing gas and the oxygen adsorbed onthe metal oxide surface leads to a change in conductance[13ndash16] Perovskite powder AFeO

3 used in thick film gas

sensors can bemanufactured by different chemical methodscoprecipitation method sol-gel method and hydrothermalmethod They are used broadly due to their advantage inwhich precursors can be admixed at atomic scale So theproducts are pure and homogeneous The products also havesmall grain size and great surface area and are compatible inmetal oxide semiconductor (MOS) gas sensors

In this paper La1minus119909

Nd119909FeO3(0 le 119909 le 10) perovskite

oxides were prepared by a citrate-gel method The influenceof Nd doping on the A site of the crystalline structure ofLaFeO

3and also on their ethanol-sensing characteristics has

been investigated in detail

2 Experimental

Nanopowders of La1minus119909

Nd119909FeO3(0 le 119909 le 10) were

prepared by a sol-gel (citrate-gel) method which is basedon the chelation of the metal cations by citric acid in asolution of water The specified amount of Fe(NO

3)3sdot9H2O

La(NO3)3sdot6H2O and Nd(NO

3)3sdot6H2O was first dissolved

Hindawi Publishing CorporationAdvances in Materials Science and EngineeringVolume 2014 Article ID 685715 5 pageshttpdxdoiorg1011552014685715

2 Advances in Materials Science and Engineering

in citric acid solution and then mixture was stirred slowlyand kept at a temperature of 70∘C until the reaction mix-ture became clear To completely create compound mattersammonium solution was added drop by drop at a time untilthe pH reached 6 and 7 The complete dissolution of the saltsresulted in a transparent solution After continuously stirringfor 2 hours the brown semitransparent sol was producedand then the solution containing La Fe and Nd cationswas homogenized the solution became more viscous as thetemperature was continuously kept at 70∘C without showingany visible phase separation This resin was placed in afurnace and dried to 120∘C for 4 h in air to pulverize intopowders The crystalline phase was obtained by heating thepowder 500∘C for 10 h in air

Structural characterization was performed by means ofX-ray diffraction using a D5005 diffractometer with Cu K120572radiation and with 2120579 varied in the range of 10ndash70∘ at a stepsize of 002∘The particle size andmorphology of the calcinedpowders were examined by SEM (119878-4800) Hitachi-Japan

The fabrication of thick films structure of sensor pro-totypes and measuring conditions were described in [17]In order to improve their stability and repeatability thethick film sensors were calcined at 400∘C for 2 h in air Thegas sensitivity of LaFe

1minus119909Nd119909O3sensors was measured in

a temperature range of 100∘Cndash300∘C Their resistance wasmeasured in air with test gas equipmentThe response 119878 wasdefined by the following equation

119878 =

119877gas minus 119877air

119877air (1)

where 119877air is the resistance of sensor measured in air and119877gas is the resistance of sensors measured in the test gasequipment

3 Result and Discussion

XRD patterns of the La1minus119909

Nd119909FeO3(0 le 119909 le 10)

samples were shown in Figure 1 All of them are single phasewith orthorhombic structure (space group Pnma) The widediffraction peaks (in position of 2120579 about 32-33∘) show thatthe samples have small grain sizeThe a-cell parameter versusNd content is presented in Figure 2 and it can be seen that thea-cell parameter of the samples decreases with the increaseof Nd doping concentration The lattice distortion may becaused by the radius of Nd3+ (0127 A) that is smaller thanone of La3+ (0136 A) It leads to the decrease of the latticeparameters with increase of the Nd concentration (Figure 2)

The crystalline sizes119863 (nm) of the samples are calculatedby Scherrer formula

119863 =119896120582

119861 cos 120579 (2)

where 119863 is the average size of crystalline particle assumingthat particles are spherical 119896 = 094 120582 is the wavelength of X-ray radiation119861 is full width at halfmaximumof the diffractedpeak and 120579 is angle of diffraction

The cell parameters and the crystalline sizes ofLa1minus119909

Nd119909FeO3powdersare shown in Table 1 These small

10 20 30 40 50 60 70

2120579 (deg)

(101)

(121)

(220)(202) (240)

(242)

x = 00

x = 015

x = 03

x = 05

x = 10

Figure 1 XRD patterns of La1minus119909

Nd119909FeO3nanoparticles after

annealing in air at 500∘C for 10 hours

00 02 04 06 08 10

557

556

555

554

553

552

551

550

310 315 320 325 330 335 340

x = 015

x = 03

x = 05

x = 10

Nd content

apa

ram

eter

(A)

LaFeO3

Figure 2 a-Cell parameter versus Nd content

grain sizes of the La1minus119909

Nd119909FeO3(0 le 119909 le 10) nanopowders

are favourable for preparing the thick film sensorsThe thick film sensors were prepared by using the

nanopowder La1minus119909

Nd119909FeO3and their ethanol-sensing char-

acters were studied The resistance of these sensors wasexaminated with the different temperatures and ethanol con-centrations Figure 3 presents the temperature dependenceof resistance of thick film sensors based on the nanosizedLa1minus119909

Nd119909FeO3in the temperature range from 160∘C to 300∘C

in air It is suggested that the electrical conductivity mecha-nism is small polaron hopping process [18 19] following theequation

120590 =119860

119879exp(minus119864119886

119896119879) (3)

Advances in Materials Science and Engineering 3

Table 1 The cell parameters and crystallite sizes of La1minus119909

Nd119909FeO3powders

119909 Compounds 119886 (A) 119887 (A) 119888 (A) 119881 (A)3 119863 (nm)0 LaFeO3 55656 52544 75659 221256 2031015 La085Nd015FeO3 55538 52432 75498 219850 1962030 La07Nd03FeO3 554500 52350 75379 218811 2124050 La05Nd05FeO3 55406 52308 75319 218280 19341 NdFeO3 55046 51967 74829 214050 1740

Table 2 The Activation energy (119864119886) of the electrical conduction process

La1minus119909

Nd119909FeO3(0 le 119909 le 10) 119909 = 00 119909 = 015 119909 = 03 119909 = 05 119909 = 10

119864119886(kJmolminus1) 27 28 26 27 20

160 180 200 220 240 260 280

0

100

200

300

400

500

600

700

Resis

tanc

e (times104

Ohm

)

Temperature (∘C)

x = 015

x = 03

x = 05

x = 10

x = 00

Figure 3 Resistance versus temperature of La1minus119909

Nd119909FeO3(119909 =

00ndash10) measured in air

where 119860 is constant relating to carrier concentration 119879 isthe temperature 119896 is the Boltzmann constant and 119864

119886is

activation energy Figure 4 shows the temperature dependenton conductivity and Figure 5 demonstrates the Arrheniusplots of conductivities of the La

1minus119909Nd119909FeO3samples From

Figure 5 the activation energy 119864119886can be calculated (Table 2)

It is noted that the resistance was decreased with increas-ing temperature due to an intrinsic characteristic of a semi-conductor This would result from the ionization of oxygenvacancies LaFeO

3and doped-LaFeO

3are the kind of p-type

semiconductive material [20]When the sensor is exposed to ethanol the ethanol reacts

with the chemisorbed oxygen releasing electrons back tothe valence band decreasing the holes concentration andincreasing resistance [16] Figure 6 depicts the response andrecovery curve of La

07Nd03FeO3when exposed to 025mgL

ethanol at 212∘C The response and recovery times of this

35 40 45 50 55 60

0

50

100

150

200

250

300

350

400

minus50

x = 015

x = 03

x = 05

x = 10

x = 00

1000T (Kminus1)

120590T

(times10minus4

S cm

minus1

K)

Figure 4 Electrical conductivity versus temperature ofLa1minus119909

Nd119909FeO3(119909 = 00ndash10) measured in air

sensor are relatively short The doping at A site caused adisorder in structure and oxygen deficiency can occur duringheating sample at high temperature On the other handLa1minus119909

Nd119909FeO3interacts with the oxygen by transferring

the electrons from the valence band to adsorbed oxygenatoms forming ionic species such as O2minus or Ominus The electrontransferring from the valence band to the chemisorbedoxygen results in an increase in holes concentration and areduction in resistance of these sensors

The temperature dependence of the La1minus119909

Nd119909FeO3sen-

sor responses to 025mgL ethanol is shown in Figure 7We found that the sensorsrsquo sensitivity increases with Ndreplaced concentration On the other hand the temper-ature at which sensor responses reach maximum valuedecreases with increasing Nd replaced concentrations Allsensors showed excellent ethanol-sensing characteristicsTheresponse of La

1minus119909Nd119909FeO3was positive this suggests that


minus2

minus1

x = 015

x = 03

x = 05

x = 10

x = 00

1000T (Kminus1)

35 40 45 50 55 60

0

1

2

3

4

5

6

ln(120590T

) (times10minus4

S cm

minus1

K)

Figure 5 Arrhenius plots of electrical conductivity forLa1minus119909

Nd119909FeO3(119909 = 00ndash10)

Resis

tanc

e (104

Ohm

)

0 400 800 1200

40

80

120

160

Time (s)

La07Nd03FeO3

Figure 6 Response and recovery curve of La07Nd03FeO3when

exposed to 025mgL ethanol at 212∘C

the semiconductivity is p-type behavior Mechanism of gas-sensing is based on the oxidation-reduction on the surface ofthe material The absorbed O119899minus accelerates the reaction

C2H5OH + 6O119899minus 997888rarr 2CO

2+ 3H2O + 6119899119890minus (4)

This should give an increase in 119877gas and thus increase thesensitivity of these sensors [9ndash13]

Figure 8 presents the dependence of the response uponthe concentration of ethanol at 182∘C for the La

1minus119909Nd119909FeO3

sensorThe change of electric resistance of the La1minus119909

Nd119909FeO3

sensor is strongly affected by an increase in ethanol gasconcentration

Temperature (∘C)

x = 015

x = 03

x = 05

x = 10

x = 00

160 180 200 220 240 260 280

0

3

6

9

12

15

18

Gas

resp

onse

Figure 7 Temperature dependence of the response in 025mgLethanol of La

1minus119909Nd119909FeO3sensors

x = 015

x = 03

x = 05

x = 10

x = 00

025 030 035 040 045 050 0550

5

10

15

20

25

Gas

resp

onse

Concentration of ethanol (mgL)

Figure 8 Ethanol concentration dependence of response ofLa1minus119909

Nd119909FeO3at 182∘C

4 Conclusion

The perovskite compounds La1minus119909

Nd119909FeO3with orthorhom-

bic perovskite structure were prepared successfully by gel-citrate method With increasing of the Nd replaced con-centrations both the particle size and a-cell parameter ofthe samples decrease The La

1minus119909Nd119909FeO3nanocrystallite

materials were manufactured thick film sensors and stud-ied ethanol-sensing characters All sensors showed excel-lent ethanol-sensing characteristics The lattice structure of


La1minus119909

Nd119909FeO3is strongly distorted and this leads to the

change of the ethanol-sensing characters as function ofreplaced Nd concentrations

Conflict of Interests

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

Acknowledgment

This work was supported by Vietnamrsquos National Foundationfor Science and Technology Development (NAFOSTED)with the project code ldquo103036909rdquo

References

[1] L Zhang J Hu P Song H Qin and M Jiang ldquoElectricalproperties and ethanol-sensing characteristics of perovskiteLa1minus119883

Pb119909FeO3rdquo Sensors and Actuators B Chemical vol 114 no

2 pp 836ndash840 2006[2] V Caignaert A Maignan and B Raveau ldquoUp to 50 000 per

cent resistance variation in magnetoresistive polycrystallineperovskites Ln23Sr13MnO3 (Ln=Nd Sm)rdquo Solid State Commu-nications vol 95 no 6 pp 357ndash359 1995

[3] N Gayathri A K Raychaudhuri S K Tiwary R GundakaramA Arulraj and C N R Rao ldquoElectrical transport magnetismand magnetoresistance in ferromagnetic oxides with mixedexchange interactions a study of the La

07Ca03Mn1minusminus119909

Co119909O3

systemrdquo Physical Review B vol 56 no 3 pp 1345ndash1353 1997[4] H Taguchi M Nagao and M Shimada ldquoMechanism of metal-

insulator transition in the systems ( Ln1-xCax)MnO3-120575( Ln LaNd andGd) and (Nd01Ca 09-ySr y)MnO297rdquo Journal of SolidState Chemistry vol 97 no 2 pp 476ndash480 1992

[5] Md A Choudhury S Akhter D L Minh N D Tho and NChau ldquoLarge magnetic-entropy change above room temper-ature in the colossal magnetoresistance La

07Sr03Mn1minus119909

Ni119909O3

materialsrdquo Journal of Magnetism and Magnetic Materials vol272ndash276 pp 1295ndash1297 2004

[6] K Iwasaki T Ito M Yoshino T Matsui T Nagasaki andY Arita ldquoPower factor of La

1minus119909Sr119909FeO3and LaFe

1minus119910Ni119910O3rdquo

Journal of Alloys and Compounds vol 430 no 1-2 pp 297ndash3012007

[7] M-H Hung M D M Rao and D-S Tsai ldquoMicrostructuresand electrical properties of calcium substituted LaFeO

3as

SOFC cathoderdquo Materials Chemistry and Physics vol 101 no2-3 pp 297ndash302 2007

[8] D Bayraktar F Clemens S Diethelm T Graule J Van herleand P Holtappels ldquoProduction and properties of substitutedLaFeO

3-perovskite tubular membranes for partial oxidation of

methane to syngasrdquo Journal of the European Ceramic Societyvol 27 no 6 pp 2455ndash2461 2007

[9] X Liu B Cheng J Hu H Qin and M Jiang ldquoSemiconductinggas sensor for ethanol based on LaMg

119909Fe1minus119909

O3nanocrystalsrdquo

Sensors and Actuators B Chemical vol 129 no 1 pp 53ndash582008

[10] H Suo F Wu Q Wang et al ldquoStudy on ethanol sensitivity ofnanocrystalline La

07Sr03FeO3-based gas sensorrdquo Sensors and

Actuators B vol 45 no 3 pp 245ndash249 1997

[11] L Chena J Hua S Fanga et al ldquoEthanol-sensing properties ofSmFe

1minus119909Ni119909O3perovskite oxidesrdquo Sensors and Actuators B vol

139 pp 407ndash410 2009[12] N N Toan S Saukko and V Lantto ldquoGas sensing with semi-

conducting perovskite oxide LaFeO3rdquo Physica B Condensed

Matter vol 327 no 2ndash4 pp 279ndash282 2003[13] J Xu J Han Y Zhang Y Sun and B Xie ldquoStudies on alcohol

sensing mechanism of ZnO based gas sensorsrdquo Sensors andActuators B Chemical vol 132 no 1 pp 334ndash339 2008

[14] J R Stetter W R Penrose and S Yao ldquoSensors chemicalsensors electrochemical sensors and ECSrdquo Journal of theElectrochemical Society vol 150 no 2 pp S11ndashS16 2003

[15] H Suo J Wang E Wu G Liu B Xu and M Zhao ldquoInfluenceof Sr content on the ethanol sensitivity of nanocrystallineLa1minus119909

Sr119909FeO3rdquo Journal of Solid State Chemistry vol 130 pp

152ndash153 1997[16] L Zhang J Hu P Song H Qin and M Jiang ldquoElectrical

properties and ethanol-sensing characteristics of perovskite1198711198861minus1199091198751198871199091198651198901198743rdquo Sensors and Actuators B vol 114 pp 836ndash840

2006[17] H T Giang H T Duy P Q Ngan G H Thai D T A Thu

and N N Toan ldquoHydrocarbon gas sensing of nano-crystallineperovskite oxides LnFeO

3(Ln = La Nd and Sm)rdquo Sensors and

Actuators B Chemical vol 158 no 1 pp 246ndash251 2011[18] M Hung M V M Rao and D Tsai ldquoMicrostructures and

electrical properties of calcium substituted LaFeO3 as SOFCcathoderdquo Materials Chemistry and Physics vol 101 no 2-3 pp297ndash302 2007

[19] S Komine and E Iguchi ldquoDielectric properties in LaFe05

Ga05

O3rdquo Journal of Physics and Chemistry of Solids vol 68 no 8 pp

1504ndash1507 2007[20] K Iwasaki T Ito M Yoshino T Matsui T Nagasaki and

Y Arita ldquoPower factor of La1minus119909

SrxFeO3and LaFe

1minus119910NiyO

3rdquo


Submit your manuscripts athttpwwwhindawicom

ScientificaHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

CorrosionInternational Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Polymer ScienceInternational Journal of



CeramicsJournal of


CompositesJournal of

NanoparticlesJournal of



International Journal of

Biomaterials


NanoscienceJournal of

TextilesHindawi Publishing Corporation httpwwwhindawicom Volume 2014

Journal of

NanotechnologyHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Journal of

CrystallographyJournal of


The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014


CoatingsJournal of

Advances in

Materials Science and EngineeringHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Smart Materials Research



MetallurgyJournal of


BioMed Research International

MaterialsJournal of


Nano

materials


Journal ofNanomaterials


in citric acid solution and then mixture was stirred slowlyand kept at a temperature of 70∘C until the reaction mix-ture became clear To completely create compound mattersammonium solution was added drop by drop at a time untilthe pH reached 6 and 7 The complete dissolution of the saltsresulted in a transparent solution After continuously stirringfor 2 hours the brown semitransparent sol was producedand then the solution containing La Fe and Nd cationswas homogenized the solution became more viscous as thetemperature was continuously kept at 70∘C without showingany visible phase separation This resin was placed in afurnace and dried to 120∘C for 4 h in air to pulverize intopowders The crystalline phase was obtained by heating thepowder 500∘C for 10 h in air

Structural characterization was performed by means ofX-ray diffraction using a D5005 diffractometer with Cu K120572radiation and with 2120579 varied in the range of 10ndash70∘ at a stepsize of 002∘The particle size andmorphology of the calcinedpowders were examined by SEM (119878-4800) Hitachi-Japan

The fabrication of thick films structure of sensor pro-totypes and measuring conditions were described in [17]In order to improve their stability and repeatability thethick film sensors were calcined at 400∘C for 2 h in air Thegas sensitivity of LaFe

1minus119909Nd119909O3sensors was measured in

a temperature range of 100∘Cndash300∘C Their resistance wasmeasured in air with test gas equipmentThe response 119878 wasdefined by the following equation

119878 =

119877gas minus 119877air

119877air (1)

where 119877air is the resistance of sensor measured in air and119877gas is the resistance of sensors measured in the test gasequipment

3 Result and Discussion

XRD patterns of the La1minus119909

Nd119909FeO3(0 le 119909 le 10)

samples were shown in Figure 1 All of them are single phasewith orthorhombic structure (space group Pnma) The widediffraction peaks (in position of 2120579 about 32-33∘) show thatthe samples have small grain sizeThe a-cell parameter versusNd content is presented in Figure 2 and it can be seen that thea-cell parameter of the samples decreases with the increaseof Nd doping concentration The lattice distortion may becaused by the radius of Nd3+ (0127 A) that is smaller thanone of La3+ (0136 A) It leads to the decrease of the latticeparameters with increase of the Nd concentration (Figure 2)

The crystalline sizes119863 (nm) of the samples are calculatedby Scherrer formula

119863 =119896120582

119861 cos 120579 (2)

where 119863 is the average size of crystalline particle assumingthat particles are spherical 119896 = 094 120582 is the wavelength of X-ray radiation119861 is full width at halfmaximumof the diffractedpeak and 120579 is angle of diffraction

The cell parameters and the crystalline sizes ofLa1minus119909

Nd119909FeO3powdersare shown in Table 1 These small

10 20 30 40 50 60 70

2120579 (deg)

(101)

(121)

(220)(202) (240)

(242)

x = 00

x = 015

x = 03

x = 05

x = 10

Figure 1 XRD patterns of La1minus119909

Nd119909FeO3nanoparticles after

annealing in air at 500∘C for 10 hours

00 02 04 06 08 10

557

556

555

554

553

552

551

550

310 315 320 325 330 335 340

x = 015

x = 03

x = 05

x = 10

Nd content

apa

ram

eter

(A)

LaFeO3

Figure 2 a-Cell parameter versus Nd content

grain sizes of the La1minus119909

Nd119909FeO3(0 le 119909 le 10) nanopowders

are favourable for preparing the thick film sensorsThe thick film sensors were prepared by using the

nanopowder La1minus119909

Nd119909FeO3and their ethanol-sensing char-

acters were studied The resistance of these sensors wasexaminated with the different temperatures and ethanol con-centrations Figure 3 presents the temperature dependenceof resistance of thick film sensors based on the nanosizedLa1minus119909

Nd119909FeO3in the temperature range from 160∘C to 300∘C

in air It is suggested that the electrical conductivity mecha-nism is small polaron hopping process [18 19] following theequation

120590 =119860

119879exp(minus119864119886

119896119879) (3)



Nd119909FeO3powders



La1minus119909

Nd119909FeO3(0 le 119909 le 10) 119909 = 00 119909 = 015 119909 = 03 119909 = 05 119909 = 10

119864119886(kJmolminus1) 27 28 26 27 20

160 180 200 220 240 260 280

0

100

200

300

400

500

600

700

Resis

tanc

e (times104

Ohm

)

Temperature (∘C)

x = 015

x = 03

x = 05

x = 10

x = 00


Nd119909FeO3(119909 =



119886is





3and doped-LaFeO






35 40 45 50 55 60

0

50

100

150

200

250

300

350

400

minus50

x = 015

x = 03

x = 05

x = 10

x = 00

1000T (Kminus1)

120590T

(times10minus4

S cm

minus1

K)







Nd119909FeO3sen-




minus2

minus1

x = 015

x = 03

x = 05

x = 10

x = 00

1000T (Kminus1)

35 40 45 50 55 60

0

1

2

3

4

5

6

ln(120590T

) (times10minus4

S cm

minus1

K)


Nd119909FeO3(119909 = 00ndash10)

Resis

tanc

e (104

Ohm

)

0 400 800 1200

40

80

120

160

Time (s)

La07Nd03FeO3





2+ 3H2O + 6119899119890minus (4)





Nd119909FeO3


Temperature (∘C)

x = 015

x = 03

x = 05

x = 10

x = 00

160 180 200 220 240 260 280

0

3

6

9

12

15

18

Gas

resp

onse



x = 015

x = 03

x = 05

x = 10

x = 00

025 030 035 040 045 050 0550

5

10

15

20

25

Gas

resp

onse




4 Conclusion







La1minus119909





Acknowledgment


References







Co119909O3





Ni119909O3







3as






119909Fe1minus119909

O3nanocrystalsrdquo






















Ga05




SrxFeO3and LaFe

1minus119910NiyO

3rdquo









CeramicsJournal of







Biomaterials




Journal of


Journal of





CoatingsJournal of

Advances in








MaterialsJournal of


Nano

materials





Nd119909FeO3powders



La1minus119909

Nd119909FeO3(0 le 119909 le 10) 119909 = 00 119909 = 015 119909 = 03 119909 = 05 119909 = 10

119864119886(kJmolminus1) 27 28 26 27 20

160 180 200 220 240 260 280

0

100

200

300

400

500

600

700

Resis

tanc

e (times104

Ohm

)

Temperature (∘C)

x = 015

x = 03

x = 05

x = 10

x = 00


Nd119909FeO3(119909 =



119886is





3and doped-LaFeO






35 40 45 50 55 60

0

50

100

150

200

250

300

350

400

minus50

x = 015

x = 03

x = 05

x = 10

x = 00

1000T (Kminus1)

120590T

(times10minus4

S cm

minus1

K)







Nd119909FeO3sen-




minus2

minus1

x = 015

x = 03

x = 05

x = 10

x = 00

1000T (Kminus1)

35 40 45 50 55 60

0

1

2

3

4

5

6

ln(120590T

) (times10minus4

S cm

minus1

K)


Nd119909FeO3(119909 = 00ndash10)

Resis

tanc

e (104

Ohm

)

0 400 800 1200

40

80

120

160

Time (s)

La07Nd03FeO3





2+ 3H2O + 6119899119890minus (4)





Nd119909FeO3


Temperature (∘C)

x = 015

x = 03

x = 05

x = 10

x = 00

160 180 200 220 240 260 280

0

3

6

9

12

15

18

Gas

resp

onse



x = 015

x = 03

x = 05

x = 10

x = 00

025 030 035 040 045 050 0550

5

10

15

20

25

Gas

resp

onse




4 Conclusion







La1minus119909





Acknowledgment


References







Co119909O3





Ni119909O3







3as






119909Fe1minus119909

O3nanocrystalsrdquo






















Ga05




SrxFeO3and LaFe

1minus119910NiyO

3rdquo









CeramicsJournal of







Biomaterials




Journal of


Journal of





CoatingsJournal of

Advances in








MaterialsJournal of


Nano

materials




minus2

minus1

x = 015

x = 03

x = 05

x = 10

x = 00

1000T (Kminus1)

35 40 45 50 55 60

0

1

2

3

4

5

6

ln(120590T

) (times10minus4

S cm

minus1

K)


Nd119909FeO3(119909 = 00ndash10)

Resis

tanc

e (104

Ohm

)

0 400 800 1200

40

80

120

160

Time (s)

La07Nd03FeO3





2+ 3H2O + 6119899119890minus (4)





Nd119909FeO3


Temperature (∘C)

x = 015

x = 03

x = 05

x = 10

x = 00

160 180 200 220 240 260 280

0

3

6

9

12

15

18

Gas

resp

onse



x = 015

x = 03

x = 05

x = 10

x = 00

025 030 035 040 045 050 0550

5

10

15

20

25

Gas

resp

onse




4 Conclusion







La1minus119909





Acknowledgment


References







Co119909O3





Ni119909O3







3as






119909Fe1minus119909

O3nanocrystalsrdquo






















Ga05




SrxFeO3and LaFe

1minus119910NiyO

3rdquo









CeramicsJournal of







Biomaterials




Journal of


Journal of





CoatingsJournal of

Advances in








MaterialsJournal of


Nano

materials




La1minus119909





Acknowledgment


References







Co119909O3





Ni119909O3







3as






119909Fe1minus119909

O3nanocrystalsrdquo






















Ga05




SrxFeO3and LaFe

1minus119910NiyO

3rdquo









CeramicsJournal of







Biomaterials




Journal of


Journal of





CoatingsJournal of

Advances in








MaterialsJournal of


Nano

materials










CeramicsJournal of







Biomaterials




Journal of


Journal of





CoatingsJournal of

Advances in








MaterialsJournal of


Nano

materials



Documents

Research Article Structural, Electrical, and Ethanol-Sensing …downloads.hindawi.com/journals/amse/2014/685715.pdf · it was also found that the LaMg 0.1 Fe 0.9 O 3 based sensor