Influence of heating temperature on Nd-Sr-Mn-O manganites synthesised via thermal treatment and sol-gel method
Mixed-valence manganites have garnered significant interest owing to their intriguing colossal magnetoresistance effect. In the realm of manganites, the primary challenge is achieving remarkable magnetoresistance (MR) values even with weak magnetic fields, rendering these materials applicable for...
| Main Author: | |
|---|---|
| Format: | Thesis |
| Language: | English |
| Published: |
2023
|
| Subjects: | |
| Online Access: | http://psasir.upm.edu.my/id/eprint/118749/ http://psasir.upm.edu.my/id/eprint/118749/1/118749.pdf |
| _version_ | 1848867776856326144 |
|---|---|
| author | Hon, Xiao Tong |
| author_facet | Hon, Xiao Tong |
| author_sort | Hon, Xiao Tong |
| building | UPM Institutional Repository |
| collection | Online Access |
| description | Mixed-valence manganites have garnered significant interest owing to their intriguing
colossal magnetoresistance effect. In the realm of manganites, the primary challenge is
achieving remarkable magnetoresistance (MR) values even with weak magnetic fields,
rendering these materials applicable for the utilisation of magnetic sensors near room
temperatures. The selection of preparation methods and synthesis routes is crucial as it
can alter the grain size formation and/or distribution, subsequently affecting the magnetic
and electrical behaviour of manganite materials. In this project, a newly developed
approach known as the thermal treatment method (TT) was employed to synthesise
Nd0.7Sr0.3MnO3 (NSMO) manganites. Given the novelty of this approach, optimisation
and fine-tuning of heat treatment parameters are imperative to achieve the utmost
desirable physical properties. The first part of this investigation focuses on assessing the
impact of calcination temperatures on the NSMO samples. Higher crystallinity was
achieved when NSMO was calcined at 500 °C and 900 °C. However, an unfavorable
morphology was observed in sample calcined at 900 °C and sintered at 1200 °C. Besides,
the NSMO samples exhibited distinct magnetic phase transition when calcined at 500 °C.
Regarding magneto-transport behaviour, the intrinsic MR is more predominant in the
sample calcined at 500 °C and sintered at 1200 °C. Thus, it can be deduced that 500 °C
is the optimum calcination temperature. The next part of this thesis aims to explore the
grain size effect on the NSMO samples synthesised via thermal treatment and sol-gel
(SG) methods at various sintering temperatures (700 °C to 1200 °C). While the sol-gel
method yielded a single NSMO phase, minor phases were detected in the NSMO samples
prepared using the thermal treatment method at a lower sintering temperature. XRD
result indicated larger crystallite size formation and better crystallinity in SG, but SEM
analysis revealed a greater variation of grain size in TT. Additionally, TT exhibited a
broader magnetic phase transition due to the existence of nonferromagnetic clusters
resulting from the detected minor phases. In both series of samples, the presence of MR
peaks suggests the prevalence of intrinsic MR, with peak intensity increasing as the
sintering temperature rises. Interestingly, contrary to prior research, the intrinsic MR is
more dominant in SG samples with smaller grain sizes, which can be attributed to the
microstructure change and morphology variations. In conclusion, this study highlights
the significance of structural and microstructural formation resulting from various
synthesis methods in governing the physical properties of manganite samples. This study
stands out as the pioneer in preparing Nd-based manganites using the thermal treatment
method. It offers the advantages of being cost-effective and environmentally friendly,
while also featuring a simplified preparation method for manganites. |
| first_indexed | 2025-11-15T14:41:53Z |
| format | Thesis |
| id | upm-118749 |
| institution | Universiti Putra Malaysia |
| institution_category | Local University |
| language | English |
| last_indexed | 2025-11-15T14:41:53Z |
| publishDate | 2023 |
| recordtype | eprints |
| repository_type | Digital Repository |
| spelling | upm-1187492025-08-04T08:31:20Z http://psasir.upm.edu.my/id/eprint/118749/ Influence of heating temperature on Nd-Sr-Mn-O manganites synthesised via thermal treatment and sol-gel method Hon, Xiao Tong Mixed-valence manganites have garnered significant interest owing to their intriguing colossal magnetoresistance effect. In the realm of manganites, the primary challenge is achieving remarkable magnetoresistance (MR) values even with weak magnetic fields, rendering these materials applicable for the utilisation of magnetic sensors near room temperatures. The selection of preparation methods and synthesis routes is crucial as it can alter the grain size formation and/or distribution, subsequently affecting the magnetic and electrical behaviour of manganite materials. In this project, a newly developed approach known as the thermal treatment method (TT) was employed to synthesise Nd0.7Sr0.3MnO3 (NSMO) manganites. Given the novelty of this approach, optimisation and fine-tuning of heat treatment parameters are imperative to achieve the utmost desirable physical properties. The first part of this investigation focuses on assessing the impact of calcination temperatures on the NSMO samples. Higher crystallinity was achieved when NSMO was calcined at 500 °C and 900 °C. However, an unfavorable morphology was observed in sample calcined at 900 °C and sintered at 1200 °C. Besides, the NSMO samples exhibited distinct magnetic phase transition when calcined at 500 °C. Regarding magneto-transport behaviour, the intrinsic MR is more predominant in the sample calcined at 500 °C and sintered at 1200 °C. Thus, it can be deduced that 500 °C is the optimum calcination temperature. The next part of this thesis aims to explore the grain size effect on the NSMO samples synthesised via thermal treatment and sol-gel (SG) methods at various sintering temperatures (700 °C to 1200 °C). While the sol-gel method yielded a single NSMO phase, minor phases were detected in the NSMO samples prepared using the thermal treatment method at a lower sintering temperature. XRD result indicated larger crystallite size formation and better crystallinity in SG, but SEM analysis revealed a greater variation of grain size in TT. Additionally, TT exhibited a broader magnetic phase transition due to the existence of nonferromagnetic clusters resulting from the detected minor phases. In both series of samples, the presence of MR peaks suggests the prevalence of intrinsic MR, with peak intensity increasing as the sintering temperature rises. Interestingly, contrary to prior research, the intrinsic MR is more dominant in SG samples with smaller grain sizes, which can be attributed to the microstructure change and morphology variations. In conclusion, this study highlights the significance of structural and microstructural formation resulting from various synthesis methods in governing the physical properties of manganite samples. This study stands out as the pioneer in preparing Nd-based manganites using the thermal treatment method. It offers the advantages of being cost-effective and environmentally friendly, while also featuring a simplified preparation method for manganites. 2023-12 Thesis NonPeerReviewed text en http://psasir.upm.edu.my/id/eprint/118749/1/118749.pdf Hon, Xiao Tong (2023) Influence of heating temperature on Nd-Sr-Mn-O manganites synthesised via thermal treatment and sol-gel method. Masters thesis, Universiti Putra Malaysia. http://ethesis.upm.edu.my/id/eprint/18409 Manganites Magnetoresistance materials Crystallization |
| spellingShingle | Manganites Magnetoresistance materials Crystallization Hon, Xiao Tong Influence of heating temperature on Nd-Sr-Mn-O manganites synthesised via thermal treatment and sol-gel method |
| title | Influence of heating temperature on Nd-Sr-Mn-O manganites synthesised via thermal treatment and sol-gel method |
| title_full | Influence of heating temperature on Nd-Sr-Mn-O manganites synthesised via thermal treatment and sol-gel method |
| title_fullStr | Influence of heating temperature on Nd-Sr-Mn-O manganites synthesised via thermal treatment and sol-gel method |
| title_full_unstemmed | Influence of heating temperature on Nd-Sr-Mn-O manganites synthesised via thermal treatment and sol-gel method |
| title_short | Influence of heating temperature on Nd-Sr-Mn-O manganites synthesised via thermal treatment and sol-gel method |
| title_sort | influence of heating temperature on nd-sr-mn-o manganites synthesised via thermal treatment and sol-gel method |
| topic | Manganites Magnetoresistance materials Crystallization |
| url | http://psasir.upm.edu.my/id/eprint/118749/ http://psasir.upm.edu.my/id/eprint/118749/ http://psasir.upm.edu.my/id/eprint/118749/1/118749.pdf |