臺灣博碩士論文加值系統

本實驗測量了絕緣體PrBa2Cu3O7-y (y = 0.05, 0.11, 0.21, 0.26, 0.57, 0.62, 0.79)和Pr1+xBa2-xCu3O7-y (x = 0.2, 0.4, 0.6, 0.8, 1.0) 的Pr L3-edge 和 Cu K-edge XANES X光邊緣吸收光譜. PrBa2Cu3O7-y的反磁序溫度TN 由 18.5 K (氧含量參數y = 0.05) 線性的下降到11K (氧含量參數y = 0.79). Pr L3-edge (2p-5d transition) 的X光邊緣吸收光譜指出Pr的價數由3.17 (y = 0.05)下降到3.01 (y = 0.79). Cu K-edge (1s-4p transition) 的X光邊緣吸收光譜指出吸收邊緣能量由8982.2 eV (y = 0.05)平移到8980.2 eV (y = 0.79).由Cu K-edge X光邊緣吸收光譜可以看出隨著電洞的參雜(氧含量參數y減少)其峰值有系統的變化, 可知道和氧含量有密切的關係.

The Pr L3-edge and Cu K-edge x-ray absorption near-edge spectra (XANES) data for the insulating PrBa2Cu3O7-y (y = 0.05, 0.11, 0.21, 0.26, 0.57, 0.62, 0.79) and Pr1+xBa2-xCu3O7-y (x = 0.2, 0.4, 0.6, 0.8, 1.0) samples are reported. The anomalous antiferromagnetic Néel temperature TN decreases monotonically from 18.5 K for oxygenated compound (y = 0.05) to 11 K for oxygen-reduced compound (y = 0.79). The Pr L3-edge (2p-5d transition) XANES data indicate that the formal Pr valence decreases from 3.17 for y = 0.05 to 3.01 for y = 0.79 . The Cu K-edge (1s-4p transition) XANES data show that the threshold energy (edge inflection point) shifts from 8982.2 eV for y = 0.05 to 8980.2 eV for y = 0.79.A systematic variation was found that peak A and peak B of Cu K-edge XANES intensities increas with oxygen content (hole doping).

Abstract
Chinese Abstract
Acknowledgments
Contents
List of Tables and Figures
Table I ~ III
Chapter 1 Introduction
1-1. Review of 123 systems
1-2 Crystal structure of Pr1+xBa2-xCu3O7-y System
1-3. Pr-O hybridization of PrBa2Cu3O7 systems
Fig.1.1~Fig.1.4
Chapter 2 Experimental Details
2-1 Sample Preparation
2-2 Powder X-ray Diffraction Measurement
2-3 Magnetic and Magnetic Susceptibility Measurement
2-4 Identification of Oxygen Concentration
2-5 X-ray absorption near edge structure (XANES) measurements
Fig.2.1~Fig.2.6
Chapter 3 Results and Discussion
3-1 Structural and oxygen stoichiometric analysis
3-2 Magnetic properties
3-3 XANES measurements
3-4 Discussion
Fig.3.1~Fig.3.10
Chapter 4 Conclusion
References

1. M.K. Wu, J.R. Ashburn, C.J. Torng, P.H. Hor, R.L. Meng, L. Gao, Z.J. Huang, Y.Q. Wang and C.W. Chu, Phys. Rev. Lett. 58, 908 (1987).
2. H.B. Radousky, J. Mater. Res. 7, 1917 (1992), and references cited there in.
3. J.C. Ho, P.H. Hor, R.L. Meng, C.W. Chu, and C.Y. Huang, Solid State Commun. 63, 711 (1987).
4. L. Soderholm et al., Nature 328, 604 (1987).
A. Kebede et al., Phys. Rev. B 40, 4453 (1989); B. Radousky, J. Mater. Res. 7, 1917 (1992), and references cited therein.
5. R. Fehrenbacher and T. M. Rice, Phys. Rev. Lett. 70, 3471 (1993), and references cited therein.
6. Z. Zou, J. Ye, K. Oka, and Y. Nishihara, Phys. Rev. Lett. 80, 1074 (1998).
7. F. C. Zhang and T. M. Rice, Phys. Rev. B 37, 3759 (1988).
8. H. M. Luo, B. N. Lin, Y. H. Lin, H. C. Chiang, Y. Y. Hsu, T. I. Hsu, T. J. Lee, H. C. Ku, C. H. Lin, H.-C. I. Kao, J. B. Shi, J. C. Ho, C. H. Chang, S. R. Hwang, and W.-H. Li., Phys. Rev. B 61, 14825 (2000).
9. H. C. Ku, Y. Y. Hsu, and B. N. Lin, J. Phys. & Chem. Solids, in press (2001), and references cited therein.
10. E. Alleno et al., Physica B 259, 530 (1999).
11. U. Staub et al., Phys. Rev. B 61, 1548 (2000).