本論文在鑭錳氧113(LaZr)(MnGa)O3系統中，使用固態反應法藉由Zr4+電子摻雜，並將錳使用鎵進行化學取代，希望藉由無磁矩的Ga3+取代磁性錳的位置，研究因此而產生結構及磁性的變化，及對於龐磁阻(CMR)性質的影響。
根據X-ray數據與磁阻測量結果交叉比對發現，如果32°附近繞射峰(110)比(104)低時，可測得磁性相變。反之如果32°附近繞射峰(110)比(104)高時則樣品不會發生磁性相變。由Rietveld精算法可知，Ga=0％與Ga=5％都是屬於相同的( )空間群。
由磁阻測量發現，電阻值都隨外加磁場的增加而下降，電阻峰值溫度隨外加磁場加大而升高。另外，5％Ga的樣品電阻峰值溫度受磁場增加的幅度也較未加入的樣品小，顯見加入無磁性的Ga稀釋Mn3+離子間磁作用力所致。
隨外加磁場變大 值就會變大；最大值範圍都在220 K～250 K左右，與磁性相變範圍相同。對未摻雜樣品來說，隨著溫度降低 值是升高的，在外加5T磁場時， 幾乎都大於40％。但對加入5％Ga的樣品來說，隨溫度降低 值是降低的；且全部都小於40％。摻雜後 明顯下降，而都是起因於Ga3+稀釋的效應。
由磁性測量可知塊材La0.85Zr0.15MnO3樣品的居禮溫度 約在240K左右，而La0.85Zr0.15(Mn0.95Ga0.05)O3在約223K。摻Ga的樣品磁性飽和轉變，也較未摻Ga的樣品為慢，原因也是來自Ga的稀釋效應。
In this thesis, we study the colossal magnetoresistance property of (La0.85Zr0.15)MnO3 system by using no-magnetic moment Ga3+ ions substitution for Mn ions and its associates with the changes of structure and magnetic property in these compounds. The electron-doped manganites samples are prepared by the solid-state reaction method.
Comparing to X-ray data and magnetoresistance measurement results, it can find that if the diffraction pick (110) is stronger then pick (104) which will associate with magnetic phase change. Otherwise, if the diffraction pick (110) is weaker then pick (104) which don’t associate with magnetic phase change. Based on the “Rietveld profile-fitting method”, the all samples are the same symmetric space group ( ).
The magnetoresistance (MR) are decreasing with the external field increasing. The temperature of the maximum value of MR is rising with the external field increasing. But the rising rate of 5% Ga doping sample is lower than the undoping sample due to that the no magnetic-moment Ga3+ ions were weaken the magnetic interaction between the Mn3+ ions.
The modulus of MR ratio is increasing with the external field increasing and those maximum values are between 220K and 250K that are same with the magnetic phase transition regions. The modulus of MR ratios of the undoping samples are increasing with temperature decreasing and these are almost above 40% under 5 Tesla external fields. The modulus of MR ratio of the 5% Ga doping sample is decreasing with temperature decreasing and it is almost below 40% with 5 Tesla external fields. The modulus of MR ratio is decreasing with the Ga3+ ions increasing, it is from that the Ga ions reduced magnetic interaction between the Mn ions
The Curie temperature of the Zr4+ Electron-doped La0.85Zr0.15MnO3 and La0.85Zr0.15(Mn0.95Ga0.05)O3 samples are 240K and 223K, respectively. The magnetic moment of the sample with Ga doping is saturated at lower temperature than the un-doping sample, which is due to the Ga ions’ diluted effect.
