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Effect of divalent ions (A = Ca, Ba and Sr) substitution in La-A-Mn-O manganite on structural, magnetic and electrical transport properties

Problem statement: Microstructure of the grain will influence the properties of a polycrystalline manganites when different dopant is introduced. In this work, an effort had been made to investigate the influence of Ca, Ba and Sr substitution in La site. Approach: Polycrystalline manganites compound...

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Main Authors: Lim, Kean Pah, Ng, Siau Wei, Shaari, Abdul Halim, Chen, Soo Kien, Wong, Jen Kuen
Format: Article
Language:English
Published: Science Publications 2009
Online Access:http://psasir.upm.edu.my/id/eprint/14230/1/ajassp.2009.1153.1157.pdf
http://psasir.upm.edu.my/id/eprint/14230/
http://thescipub.com/html/10.3844/ajassp.2009.1153.1157
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spelling my.upm.eprints.142302017-11-29T02:46:32Z http://psasir.upm.edu.my/id/eprint/14230/ Effect of divalent ions (A = Ca, Ba and Sr) substitution in La-A-Mn-O manganite on structural, magnetic and electrical transport properties Lim, Kean Pah Ng, Siau Wei Shaari, Abdul Halim Chen, Soo Kien Wong, Jen Kuen Problem statement: Microstructure of the grain will influence the properties of a polycrystalline manganites when different dopant is introduced. In this work, an effort had been made to investigate the influence of Ca, Ba and Sr substitution in La site. Approach: Polycrystalline manganites compound of La0.67A0.33MnO3 where A = Ba, Sr and Ca had been prepared via conventional solid-state reaction method. The structure, microstructure, magnetic and electrical properties had been investigated using XRD, SEM, VSM and four-point probe techniques. Results: XRD spectrums showed that LBMO and LCMO were in single-phase orthorhombic structure whereas LSMO was rhombohedral structure. Scanning electron micrographs showed that LSMO had smaller average grain size as compared to LBMO. However, for LCMO, there was no clear grain boundary that can be observed and all the grains were well connected. The difference in the microstructure image might be due to the variance A-site cation that differs in grain growth. The Curie temperature, Tc of LBMO and LSMO was 343.0 and 363.5 K, respectively. But the Tc for LCMO was lower then 300 K. The Tp for LCMO was 215 K while it was near or above 300K for LBMO and LSMO. All samples showed extrinsic Magnetoresistance (MR) effect. Higher MR was observed well below Tc or Tp where MR value increased monotonically with the decrease of temperature. This was associated with the different grain and grain boundary formation when different cation was substituted. LCMO displayed the highest low-field MR value (-15.82% at 0.2 T, 90 K) and high-field MR (-25.60% at 1 T, 300 K). Conclusion: Hence, electrical and magnetic transition temperature (Tp and Tc) were affected by the average A-site cation radius. Science Publications 2009 Article PeerReviewed application/pdf en http://psasir.upm.edu.my/id/eprint/14230/1/ajassp.2009.1153.1157.pdf Lim, Kean Pah and Ng, Siau Wei and Shaari, Abdul Halim and Chen, Soo Kien and Wong, Jen Kuen (2009) Effect of divalent ions (A = Ca, Ba and Sr) substitution in La-A-Mn-O manganite on structural, magnetic and electrical transport properties. American Journal of Applied Sciences, 6 (6). pp. 1153-1157. ISSN 1546-9239; ESSN: 1554-3641 http://thescipub.com/html/10.3844/ajassp.2009.1153.1157 10.3844/ajassp.2009.1153.1157
institution Universiti Putra Malaysia
building UPM Library
collection Institutional Repository
continent Asia
country Malaysia
content_provider Universiti Putra Malaysia
content_source UPM Institutional Repository
url_provider http://psasir.upm.edu.my/
language English
description Problem statement: Microstructure of the grain will influence the properties of a polycrystalline manganites when different dopant is introduced. In this work, an effort had been made to investigate the influence of Ca, Ba and Sr substitution in La site. Approach: Polycrystalline manganites compound of La0.67A0.33MnO3 where A = Ba, Sr and Ca had been prepared via conventional solid-state reaction method. The structure, microstructure, magnetic and electrical properties had been investigated using XRD, SEM, VSM and four-point probe techniques. Results: XRD spectrums showed that LBMO and LCMO were in single-phase orthorhombic structure whereas LSMO was rhombohedral structure. Scanning electron micrographs showed that LSMO had smaller average grain size as compared to LBMO. However, for LCMO, there was no clear grain boundary that can be observed and all the grains were well connected. The difference in the microstructure image might be due to the variance A-site cation that differs in grain growth. The Curie temperature, Tc of LBMO and LSMO was 343.0 and 363.5 K, respectively. But the Tc for LCMO was lower then 300 K. The Tp for LCMO was 215 K while it was near or above 300K for LBMO and LSMO. All samples showed extrinsic Magnetoresistance (MR) effect. Higher MR was observed well below Tc or Tp where MR value increased monotonically with the decrease of temperature. This was associated with the different grain and grain boundary formation when different cation was substituted. LCMO displayed the highest low-field MR value (-15.82% at 0.2 T, 90 K) and high-field MR (-25.60% at 1 T, 300 K). Conclusion: Hence, electrical and magnetic transition temperature (Tp and Tc) were affected by the average A-site cation radius.
format Article
author Lim, Kean Pah
Ng, Siau Wei
Shaari, Abdul Halim
Chen, Soo Kien
Wong, Jen Kuen
spellingShingle Lim, Kean Pah
Ng, Siau Wei
Shaari, Abdul Halim
Chen, Soo Kien
Wong, Jen Kuen
Effect of divalent ions (A = Ca, Ba and Sr) substitution in La-A-Mn-O manganite on structural, magnetic and electrical transport properties
author_facet Lim, Kean Pah
Ng, Siau Wei
Shaari, Abdul Halim
Chen, Soo Kien
Wong, Jen Kuen
author_sort Lim, Kean Pah
title Effect of divalent ions (A = Ca, Ba and Sr) substitution in La-A-Mn-O manganite on structural, magnetic and electrical transport properties
title_short Effect of divalent ions (A = Ca, Ba and Sr) substitution in La-A-Mn-O manganite on structural, magnetic and electrical transport properties
title_full Effect of divalent ions (A = Ca, Ba and Sr) substitution in La-A-Mn-O manganite on structural, magnetic and electrical transport properties
title_fullStr Effect of divalent ions (A = Ca, Ba and Sr) substitution in La-A-Mn-O manganite on structural, magnetic and electrical transport properties
title_full_unstemmed Effect of divalent ions (A = Ca, Ba and Sr) substitution in La-A-Mn-O manganite on structural, magnetic and electrical transport properties
title_sort effect of divalent ions (a = ca, ba and sr) substitution in la-a-mn-o manganite on structural, magnetic and electrical transport properties
publisher Science Publications
publishDate 2009
url http://psasir.upm.edu.my/id/eprint/14230/1/ajassp.2009.1153.1157.pdf
http://psasir.upm.edu.my/id/eprint/14230/
http://thescipub.com/html/10.3844/ajassp.2009.1153.1157
_version_ 1643825571405234176
score 13.211869

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