Electrical, magnetic and microwave absorption properties of Fe substituted La0.85Ag0.15Mn1-xFexO3 (x=0, 0.05, 0.10, 0.15 and 0.20) monovalent doped manganites / Nur Ain Athirah Che Apandi

La0.85Ag0.15Mn1-xFexO3 (x=0, 0.05, 0.10, 0.15 and 0.20) monovalent-based manganites, were prepared using conventional solid-state method to investigate the effect of Iron (Fe) substitution on the electrical, magnetic and microwave absorption properties. The phase identification were investigated usi...

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Main Author:	Che Apandi, Nur Ain Athirah
Format:	Thesis
Language:	English
Published:	2022
Subjects:	Atomic physics Constitution and properties of matter Physical and theoretical chemistry
Online Access:	https://ir.uitm.edu.my/id/eprint/72940/1/72940.pdf
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spelling	my-uitm-ir.729402023-02-01T13:54:07Z Electrical, magnetic and microwave absorption properties of Fe substituted La0.85Ag0.15Mn1-xFexO3 (x=0, 0.05, 0.10, 0.15 and 0.20) monovalent doped manganites / Nur Ain Athirah Che Apandi 2022 Che Apandi, Nur Ain Athirah Atomic physics. Constitution and properties of matter Physical and theoretical chemistry La0.85Ag0.15Mn1-xFexO3 (x=0, 0.05, 0.10, 0.15 and 0.20) monovalent-based manganites, were prepared using conventional solid-state method to investigate the effect of Iron (Fe) substitution on the electrical, magnetic and microwave absorption properties. The phase identification were investigated using X-ray diffraction (XRD) pattern, showed all samples are single phase rhombohedral crystal structure. From temperature dependence resistivity curves, it was found that the Fe substitution increased the resistivity in the temperature region of 30 310 K and decrease in metal-insulator transition temperature, TMI from 239.93 K to 67.97 K for x=0 0.10 while for x=0.15 and 0.20, the samples exhibit insulating behavior for the whole temperature region. The decreased in TMI indicates weakening of double exchange mechanism due to reduction of Mn3+/Mn4+ ratio as Mn3+ concentration decreased as a result of substitution. From real part of susceptibiltiy,’ vs temperature curves, ferromagnetic-paramagnetic transition temperature, Tc was found to be decreased from 299.06 K (x=0) to 141.85 K (x=0.20) indicates Fe substitution weakened ferromagnetic interactions between Mn ions. Fe substitution is suggested to increase the scattering effects in metallic region as electron-electron and electron-magnon scattering parameters increased with Fe concentration of x=0, 0.05 and 0.10. While in the insulating region, the substitution enhances electron-phonon coupling as activation energy, Ea and hopping energy, Eh increased with Fe concentration from 101.55 meV (x=0) to 161.07 meV (x=0.20) and 40.97 meV (x=0) to 139.38 meV (x=0.20), respectively. Microwave absorption performance which implies by value of reflection loss, RL measurements in the frequency range of 8 GHz to 18 GHz showed the highest reflection loss for x = 0 sample where value of reflection loss of 57.2 dB at 16.41 GHz with a bandwidth of 2.67 GHz corresponding to reflection loss below 10 dB was observed. However, with the increasing of Fe concentration, the RL values decreases from 29.5 dB (x=0.05), 9.8 dB (x=0.10), and 6.8 dB (x=0.15) and increase to 13.8 dB (x=0.20) at frequency 16.35 GHz, 14.79 GHz, 14.40 GHz and 16.26 GHz, respectively. It is also found that frequency of the RL peaks match the location of impedance matching, Zin/Zo minimum for each sample which in turn is influenced by the changes in sample’s resistivity due to Fe doping. The observed nearly constant of eddy current coefficient, Co value in Co vs frequency curves indicates that eddy current loss is important contributor factor for the magnetic loss mechanism for most samples in the range of matching frequency. On the other hand, measurements of imaginary part of permittivity, ɛʺ accompanied by enhanced tan δe with Fe content indicates Fe doping enhancing the dielectric loss component and contributes to microwave absorption in the samples. It is suggested that good microwave absorption performance for x=0 sample dominantly influence by its weak ferromagnetic properties. While for Fe-substituted samples, it is suggested that the large number of localized charge carrier contribute to enhancement of dielectric loss mechanisms consists of conduction loss. The observed strong absorption, coupled with wide band performance suggests the possibility of using these manganites as a new material in the design of microwave absorbers. 2022 Thesis https://ir.uitm.edu.my/id/eprint/72940/ https://ir.uitm.edu.my/id/eprint/72940/1/72940.pdf text en public masters Universiti Teknologi MARA (UiTM) Faculty of Applied Sciences Ibrahim, Norazila Awang, Zaiki Azis, Raba'ah Syahidah
institution	Universiti Teknologi MARA
collection	UiTM Institutional Repository
language	English
advisor	Ibrahim, Norazila Awang, Zaiki Azis, Raba'ah Syahidah
topic	Atomic physics Constitution and properties of matter Physical and theoretical chemistry
spellingShingle	Atomic physics Constitution and properties of matter Physical and theoretical chemistry Che Apandi, Nur Ain Athirah Electrical, magnetic and microwave absorption properties of Fe substituted La0.85Ag0.15Mn1-xFexO3 (x=0, 0.05, 0.10, 0.15 and 0.20) monovalent doped manganites / Nur Ain Athirah Che Apandi
description	La0.85Ag0.15Mn1-xFexO3 (x=0, 0.05, 0.10, 0.15 and 0.20) monovalent-based manganites, were prepared using conventional solid-state method to investigate the effect of Iron (Fe) substitution on the electrical, magnetic and microwave absorption properties. The phase identification were investigated using X-ray diffraction (XRD) pattern, showed all samples are single phase rhombohedral crystal structure. From temperature dependence resistivity curves, it was found that the Fe substitution increased the resistivity in the temperature region of 30 310 K and decrease in metal-insulator transition temperature, TMI from 239.93 K to 67.97 K for x=0 0.10 while for x=0.15 and 0.20, the samples exhibit insulating behavior for the whole temperature region. The decreased in TMI indicates weakening of double exchange mechanism due to reduction of Mn3+/Mn4+ ratio as Mn3+ concentration decreased as a result of substitution. From real part of susceptibiltiy,’ vs temperature curves, ferromagnetic-paramagnetic transition temperature, Tc was found to be decreased from 299.06 K (x=0) to 141.85 K (x=0.20) indicates Fe substitution weakened ferromagnetic interactions between Mn ions. Fe substitution is suggested to increase the scattering effects in metallic region as electron-electron and electron-magnon scattering parameters increased with Fe concentration of x=0, 0.05 and 0.10. While in the insulating region, the substitution enhances electron-phonon coupling as activation energy, Ea and hopping energy, Eh increased with Fe concentration from 101.55 meV (x=0) to 161.07 meV (x=0.20) and 40.97 meV (x=0) to 139.38 meV (x=0.20), respectively. Microwave absorption performance which implies by value of reflection loss, RL measurements in the frequency range of 8 GHz to 18 GHz showed the highest reflection loss for x = 0 sample where value of reflection loss of 57.2 dB at 16.41 GHz with a bandwidth of 2.67 GHz corresponding to reflection loss below 10 dB was observed. However, with the increasing of Fe concentration, the RL values decreases from 29.5 dB (x=0.05), 9.8 dB (x=0.10), and 6.8 dB (x=0.15) and increase to 13.8 dB (x=0.20) at frequency 16.35 GHz, 14.79 GHz, 14.40 GHz and 16.26 GHz, respectively. It is also found that frequency of the RL peaks match the location of impedance matching, Zin/Zo minimum for each sample which in turn is influenced by the changes in sample’s resistivity due to Fe doping. The observed nearly constant of eddy current coefficient, Co value in Co vs frequency curves indicates that eddy current loss is important contributor factor for the magnetic loss mechanism for most samples in the range of matching frequency. On the other hand, measurements of imaginary part of permittivity, ɛʺ accompanied by enhanced tan δe with Fe content indicates Fe doping enhancing the dielectric loss component and contributes to microwave absorption in the samples. It is suggested that good microwave absorption performance for x=0 sample dominantly influence by its weak ferromagnetic properties. While for Fe-substituted samples, it is suggested that the large number of localized charge carrier contribute to enhancement of dielectric loss mechanisms consists of conduction loss. The observed strong absorption, coupled with wide band performance suggests the possibility of using these manganites as a new material in the design of microwave absorbers.
format	Thesis
qualification_level	Master's degree
author	Che Apandi, Nur Ain Athirah
author_facet	Che Apandi, Nur Ain Athirah
author_sort	Che Apandi, Nur Ain Athirah
title	Electrical, magnetic and microwave absorption properties of Fe substituted La0.85Ag0.15Mn1-xFexO3 (x=0, 0.05, 0.10, 0.15 and 0.20) monovalent doped manganites / Nur Ain Athirah Che Apandi
title_short	Electrical, magnetic and microwave absorption properties of Fe substituted La0.85Ag0.15Mn1-xFexO3 (x=0, 0.05, 0.10, 0.15 and 0.20) monovalent doped manganites / Nur Ain Athirah Che Apandi
title_full	Electrical, magnetic and microwave absorption properties of Fe substituted La0.85Ag0.15Mn1-xFexO3 (x=0, 0.05, 0.10, 0.15 and 0.20) monovalent doped manganites / Nur Ain Athirah Che Apandi
title_fullStr	Electrical, magnetic and microwave absorption properties of Fe substituted La0.85Ag0.15Mn1-xFexO3 (x=0, 0.05, 0.10, 0.15 and 0.20) monovalent doped manganites / Nur Ain Athirah Che Apandi
title_full_unstemmed	Electrical, magnetic and microwave absorption properties of Fe substituted La0.85Ag0.15Mn1-xFexO3 (x=0, 0.05, 0.10, 0.15 and 0.20) monovalent doped manganites / Nur Ain Athirah Che Apandi
title_sort	electrical, magnetic and microwave absorption properties of fe substituted la0.85ag0.15mn1-xfexo3 (x=0, 0.05, 0.10, 0.15 and 0.20) monovalent doped manganites / nur ain athirah che apandi
granting_institution	Universiti Teknologi MARA (UiTM)
granting_department	Faculty of Applied Sciences
publishDate	2022
url	https://ir.uitm.edu.my/id/eprint/72940/1/72940.pdf
_version_	1783735963219918848

Electrical, magnetic and microwave absorption properties of Fe substituted La0.85Ag0.15Mn1-xFexO3 (x=0, 0.05, 0.10, 0.15 and 0.20) monovalent doped manganites / Nur Ain Athirah Che Apandi

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