Study on the Magnetic Properties of Nd1-xSrxMnO3 Nanoparticles
| Autor: | 蔣政諺 |
|---|---|
| Rok vydání: | 2005 |
| Druh dokumentu: | 學位論文 ; thesis |
| Popis: | 93 Doped perovskite manganites R1-xAxMnO3 (where R = rare earth, A = Ca, Sr, Ba, Ce, or Zr) have been researched widely in recent years due to their rich properties like colossal magnetoresistance, charge ordering, and orbital ordering. However, most research was carried out for bulk samples. In this thesis, we have investigated the magnetic properties of Nd1-xSrxMnO3 nanoparticles with different Sr concentration (x) and particle sizes (sintered at 700℃ and 1300℃ respectively). The samples were prepared by sol-gel method .The structure and particle size were determined by X-ray Diffractometer and Scanning Electron Microscope ( SEM ). Magnetic properties were measured by Superconducting Quantum Interference Device (SQUID) and Electron Spin Resonance Spectrometer (ESR). From the results of the M-T measurements, the ground state of the 1300℃ system of Nd1-xSrxMnO3 (x=0.4 ~ 0.6) changes from ferromagnetic to CE-type antiferromagnetic and A-type antiferromagnetic state with increasing x. For the x=0.5, 700℃ sample, we do not find the existence of the antiferromagnetic state on Nd0.5Sr0.5MnO3, which is observed in the x=0.5, 1300℃ sample. Comparing results obtained from the M-T measurements and the ESR spectrum, the 1300℃ system has properties similar to that of bulk samples, but 700℃ system does not. From the peak-to-peak linewidth obtained from the ESR spectrum above Curie temperature, we found that the smaller the particle size the less the J-T distortion. |
| Databáze: | Networked Digital Library of Theses & Dissertations |
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