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Colossal magnetoresistance of La0.67Ca0.33Mn1-xAx)3 [A=V, Dy and Zr] perovskite

The colossal magnetoresistive of Lao.67Cao.33Mnl-x V x03 (LCMVO), to x=O.30, ceramics have been studied. X-ray diffraction (XRD) patterns show single-phase perovskite structure with the presence of some minor impurities for all the samples. The systems exhibit tetragonal and orthorhombic distorted p...

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Hlavní autor: Koh, Song Foo
Médium: Diplomová práce
Jazyk:English
Vydáno: 2001
On-line přístup:http://ethesis.upm.edu.my/id/eprint/3513/1/FSAS_2001_20_F.pdf
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spelling oai:ethesis.upm.edu.my:3513 http://ethesis.upm.edu.my/id/eprint/3513/ Colossal magnetoresistance of La0.67Ca0.33Mn1-xAx)3 [A=V, Dy and Zr] perovskite Koh, Song Foo The colossal magnetoresistive of Lao.67Cao.33Mnl-x V x03 (LCMVO), to x=O.30, ceramics have been studied. X-ray diffraction (XRD) patterns show single-phase perovskite structure with the presence of some minor impurities for all the samples. The systems exhibit tetragonal and orthorhombic distorted perovskite structures, which resulted from the Jahn Teller distortion. Paramagnetic - Ferromagnetic phase transitions were observed in the X'-temperature curves for all the samples. The Curie temperature, Tc shifts to lower temperature as vanadium, dysprosium and zirconium doping increases respectively, which indicate the loss of ferromagnetic order. Zirconium doping is observed to decrease the Te more than the effect of other dopants. For LCMVO system, samples with x=0.0l, 0.02, 0.03 and 0.30 show an enhancement of volume susceptibility as the temperature increases from 110 K- 140 K, 120 K- 142 K, 123 K-140 K and 77 K-94 K respectively. These enhancements are due to the formation of magnetic clusters m the samples. For LCMDO system, all the samples show the typical ferromagnetic-paramagnetic transition and no spin glass behaviour was detected. However, in LCMZO system, the samples with x>0.05 show ferromagnetic onset followed by a cusp when cooling from room temperature. The anomalies were due to the formation of spin glass in the sample. The transport properties show the transition of semiconducting to metallic conductivity at T p. The existence of T p and T c was found correlated. 2001-04 Thesis NonPeerReviewed application/pdf en http://ethesis.upm.edu.my/id/eprint/3513/1/FSAS_2001_20_F.pdf Koh, Song Foo (2001) Colossal magnetoresistance of La0.67Ca0.33Mn1-xAx)3 [A=V, Dy and Zr] perovskite. Masters thesis, Universiti Putra Malaysia. (FSAS 2001 20).
institution UPM eTHESES
collection UPM eTHESES
language English
description The colossal magnetoresistive of Lao.67Cao.33Mnl-x V x03 (LCMVO), to x=O.30, ceramics have been studied. X-ray diffraction (XRD) patterns show single-phase perovskite structure with the presence of some minor impurities for all the samples. The systems exhibit tetragonal and orthorhombic distorted perovskite structures, which resulted from the Jahn Teller distortion. Paramagnetic - Ferromagnetic phase transitions were observed in the X'-temperature curves for all the samples. The Curie temperature, Tc shifts to lower temperature as vanadium, dysprosium and zirconium doping increases respectively, which indicate the loss of ferromagnetic order. Zirconium doping is observed to decrease the Te more than the effect of other dopants. For LCMVO system, samples with x=0.0l, 0.02, 0.03 and 0.30 show an enhancement of volume susceptibility as the temperature increases from 110 K- 140 K, 120 K- 142 K, 123 K-140 K and 77 K-94 K respectively. These enhancements are due to the formation of magnetic clusters m the samples. For LCMDO system, all the samples show the typical ferromagnetic-paramagnetic transition and no spin glass behaviour was detected. However, in LCMZO system, the samples with x>0.05 show ferromagnetic onset followed by a cusp when cooling from room temperature. The anomalies were due to the formation of spin glass in the sample. The transport properties show the transition of semiconducting to metallic conductivity at T p. The existence of T p and T c was found correlated.
format Thesis
author Koh, Song Foo
spellingShingle Koh, Song Foo
Colossal magnetoresistance of La0.67Ca0.33Mn1-xAx)3 [A=V, Dy and Zr] perovskite
author_facet Koh, Song Foo
author_sort Koh, Song Foo
title Colossal magnetoresistance of La0.67Ca0.33Mn1-xAx)3 [A=V, Dy and Zr] perovskite
title_short Colossal magnetoresistance of La0.67Ca0.33Mn1-xAx)3 [A=V, Dy and Zr] perovskite
title_full Colossal magnetoresistance of La0.67Ca0.33Mn1-xAx)3 [A=V, Dy and Zr] perovskite
title_fullStr Colossal magnetoresistance of La0.67Ca0.33Mn1-xAx)3 [A=V, Dy and Zr] perovskite
title_full_unstemmed Colossal magnetoresistance of La0.67Ca0.33Mn1-xAx)3 [A=V, Dy and Zr] perovskite
title_sort colossal magnetoresistance of la0.67ca0.33mn1-xax)3 [a=v, dy and zr] perovskite
publishDate 2001
url http://ethesis.upm.edu.my/id/eprint/3513/1/FSAS_2001_20_F.pdf
_version_ 1819310378353426432
score 13.4562235

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