Solid State Science and Technology, Vol. 20, No 1& 2 (2012) 1-10

ISSN 0128-7389

1

INFLUENCE OF SINTERING TEMPERATURE ON MICROSTRUCTURAL,

ELECTRICAL AND MAGNETO-TRANSPORT OF Nd0.68Sr0.32MnO3

L.S. Ewe1,, A.Jemat1, W. N. Voon1 and K.P.Lim2

 

1College of Foundation and General Studies, Universiti Tenaga Nasional,

Kampus Putrajaya, Jalan IKRAM-UNITEN,

43000 Kajang, Selangor, Malaysia

2Department of Physics, Faculty of Science, Universiti Putra Malaysia,

43300 UPM Serdang, Selangor, Malaysia

*Corresponding author: laysheng@uniten.edu.my

 

ABSTRACT

A systematic study on Nd0.68Sr0.32MnO3 manganites has been undertaken, primarily to

understand the influence of varying grain size on the structural, electrical resistivity and

magneto transport properties at the insulating and metallic regions. The materials were

prepared by the solid state reaction method at sintering temperature 1170oC, 1270oC

and 1350oC. The XRD patterns show all samples have a single phase with

orthorhombic structure. SEM images show a linear relationship between sintering

temperature and grain size. The insulator metal transition temperatures, Tim were

determined and remained nearly constant (~ 200 K) for samples sintered at 1270 oC and

1350oC. While for sample sintered at 1170 oC, Tim is found around 180 K. The

resistivity data fits well with equations ρ = ρo + ρ2T2 and ρ = ρo + ρ2.5T2.5 in metallic

(ferromagnetic) region. At high temperature (T>Tim) insulating (paramagnetic) region,

small polaron hopping and variable range hopping models were used to compute the

density of states at Fermi level N(EF) and the activation energy (Ea) of the electrons.

 

Keywords: magnetotransport; grain size; activation energy

 

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REFERENCES

[1] R. yon Helmolt, J. Weckerg, B. Holzapfel, L. Schultz and K. Samwer, Phys. Rev.

Lett. 71 (1993) 2331

[2] S. Jin, T.H. Tiefel, M. McCormack, R.A. Fastnacht, R. Ramesh and L.H. Chen,

Science 264 (1994) 413

[3] G.Venkataiah, D.C.Krishna, M.Vithal, S.S.Rao, S.V.Bhat, V.Prasad,

S.V.Subramanyam, P.Venugopal Reddy, Physica B 357 (2005) 370

[4] C.N.Rao and A.K. Raychaudhuri, (1998) Colossal Magnetoresistance, Charge

Ordering and Other Novel Properties of Manganates and Related Materials,

(World Scientific Singapore).

[5] H.L. Ju, J. Gopalakrishnan, J.L. Peng, Qi Li, G.C. Xiong, T. Venkatesan and R.L.

Greene, Phys. Rev. B 51 (1995) 6143

[6] G.H. Jonker and J.H. van Santen, Physica 16 (1950) 337

[7] J. Volgar, Physica 20 (1954) 49

[8] L.S. Ewe, I. Hamadneh, H. Salama, N.A. Nasri, S.A. Halim, R. Abd-Shukor, Appl

Phys A 95 (2009) 457-463

[9] R. Mahendiran, R. Mahesh, A.K. Raychaudhuri, C.N.R. Rao, Solid State

Commun. 99 (3) (1996) 149

[10] A. Banerjee, S. Pal, S. Bhattacharya, B.K. Chaudhuri, J. Appl. Phys. 91 (2002)

5125

[11] Y.L. Change and C. K. Ong, J. Phys Condens. Matter 16 (2004) 3711

[12] L. Sudheendra, H.D. Chinh, A.R. Raju, A.K. Raychaudhuri, C.N.R. Rao, Solid

State Comm. 122 (2002) 53

[13] G. Venkataiah, P. Venugopal Reddy, J. Magn. Magn. Mater. 285 (2005) 343-352

[14] P. Kameli, H. Salamati, A. Aezami, J. Alloys Compd. 450 (2008) 7

[15] B. Boy and S. Das, J. Appl. Phys. 104 (2008) 103915

[16] Y.B. Zhang, S. Li, C.Q. Sun, S. Widjaja, P. Hing, Journal of MaterialsProcessing

Technology 122 (2002) 266-271