本研究主要是在探討（磁阻材料/金屬）與（磁阻材料/氧化物）等磁阻複合物(composites)對磁傳輸行為特性的影響。探討幾近自旋極化(nearly spin polarization)鈣鈦礦複合物(composite)異質連接界面的載子傳輸特性。在低溫時和在低維度樣品中，電子的傳導行為深受到量子干涉(quantum interference)與表面效應的影響，當晶粒尺寸縮小至近奈米等級時，這些效應尤其顯著，包含庫倫力作用(Columb interaction)、雙重交換作用(Double exchange)、穿隧效應(Tunneling effect)、及載子躍遷(Carrier hopping)等介觀物理(Mesoscopic physics)的性質與機制均將極為不同。
分別研製不同成分的A/B 磁性半金屬氧化物複合物和磁性鑭錳氧化物複合物結構。以變溫直交流電阻率量測、低磁場場冷卻零場冷卻磁矩(LF FC-ZFC magnetization)、高場磁矩、磁滯曲線等的量測來研究晶粒邊界的磁傳輸特性。以不同A（磁性鑭錳氧化物）與B（金屬或氧化物）成份來調變晶粒邊界的自旋極化耦合條件，以觀察傳輸載子在晶粒邊界的傳導電子溫度倚變躍遷情形。

This study discussed the influence of magnetoresistance/metal and magnetoresistance/oxide on the magnetotransport behavior and also researched in the magnetic composites, the inter-grain carrier magneto-transport behaviors in these nearly spin polarization hetero-structural composites are investigated either. In low temperature and dimension of samples, the transport of carriers is affected markedly by the quantum interference and surface effect. While the size of grain approaching nanometer scale, the effects of mesoscopic physics including columb interaction, double interaction, tunneling effect and carrier hopping behavior will be different.
Various compositions of A/B magnetic manganite oxide composites will be synthesized to study the boundary effect on the magnetic-electric interaction by the measurements of temperature-dependent resistivity, low field FC-ZFC magnetization and magnetic hysteresis with various applied field. Then various compositions of composites to modulate the spin polarization condition in the grain boundary and observe the behavior of the temperature dependence of transport carrier hopping across grain boundary.

誌謝............................................ i
中文摘要 ....................................... ii
Abstract ....................................... iii
目 錄 .......................................... iv
圖表目錄 ........................................ v
第一章 前言 .................................... 1
第二章 理論 .................................... 5
2-1 磁性理論 ................................... 9
2-3 巨磁阻理論 ............................................. 12
2-3.1 雙重交換作用理論 ............................................. 16
2-3.2 Jahn Teller distortion ..................................... 18
第三章 研究方法 ............................................. 19
3-1藥品 ........................................ 19
3-2儀器設備 .................................... 19
第四章 結果與討討 .............................. 24
第五章 結論 .................................... 25
參 考 文 獻 .................................... 27

[1] Baibich Yan et al., Phys. Rev. Lett., Vol. 61 (1988) 2472.
[2] M. Marszaek et al., Sens. Actuatorsw A, Vol. 91 (2001) 180.
[3] R. M. Oksuzoglu et al., J. Mag. Mag. Mater., Vol. 279 (2004) 202.
[4] G. Ni et al., Solid State Comm., Vol. 127 (2003) 719.
[5] B. Aronzon et al., J. Mag. Mag. Mater., Vol. 242 (2002) 631.
[6] H. Itoh et al., J. Mag. Mag. Mater., Vol. 240 (2002) 121.
[7] G. L. Yuan, Mater. Letter, Vol. 53 (2002) 76.
[8] Pin Lyu, J. Mag. Mag. Mater., Vol. 268 (2004) 251.
[9] K. Nakajima, K. Inomata, J. Mag. Mag. Mater., Vol. 272 (2004) e1519.
[10] A. Hernando et al., J. Mag. Mag. Mater., Vol. 262 (2003) 1.
[11] M. Marszaek et al., Sens. Actuatorsw A, Vol. 106 (2003) 91.
[12] R.Von.Helmot，J.Wecker，B.Holzapfel，L.Schultz and K.Samwer，Phys. Rev. Lett. 71，2331 (1993).
[13] S.Jin，T.H.Tiefel，M.McCormack，R.A.Fastnacht，R.Ramesh and L.H.Chen，Science，264，413 (1994).
[14] S.Jin，T.H.Tiefel，M.McCormacK，H.M.O’Bryan，L.H.Chen and R.Ramesh，Appl. Phys. Lett. 67，557 (1995).
[15] M.Julliers，Phys. Lett. 54A，225 (1975).
[16] G. H. Jonker and J. H. Van Santen, Physica Vol. 16（1950）337.
[17] C. Zener, Phys. Rev., Vol. 81 (1951) 440.
[18] http://sunlab.phys.nthu.edu.tw/cmr.html
[19] 宛德福，馬興隆.“磁性物理學”，電子科技大學出版社. (1994).
[20] D.K. Petrov, L. Krusin-Elbaum, J.Z. Sun, C. Feild, P.R.
Duncombe, Appl. Phys. Lett. 75 (1999) 995.
[21] Ll. Balcells, A.E. Carrillo, B. Martínez, J. Fontcuberta, Appl.
Phys. Lett. 74 (1999) 4014.
[22] S. Gupta, R. Ranjit, C. Mitra, P. Raychaudhuri, R. Pinto, Appl.
Phys. Lett. 78 (2001) 362.
[23] Y.H. Huang, C.H. Yan, W. Song, Z.M. Wang, C.S. Liao,
Appl. Phys. Lett. 81 (2002) 76.