臺灣博碩士論文加值系統

本論文主要是探討高溫超導系統(Sm0.58Y0.42)2CuO4的結構及磁特性
。經由 X光繞射實驗，及GSAS精算程式我們可以探討樣本的精確結構，並
由交流磁化率量測結果，研究樣本在不同溫度區域的磁特性。 由 X
光繞射譜圖之精算結果，此樣本在室溫時之晶格常數為 a = b =
3.89857(21) 埃， c=11.9018(9) 埃，結構為正方晶格(I 4/m m m )，經
過變溫的X光繞射實驗後，我們確定此樣本在變溫區間(80~295K)並無結構
的改變。 而在基本磁性方面 ，在交流磁化率與溫度的關係圖中
，出現二個脈峰，在高溫 (~255 K)的脈峰為此系統的自旋玻璃性所造成
，此可由頻率與磁化率的關係來証實;在低溫(~11K)的脈峰則源自於 Sm
的反鐵磁性。

We have studied the structure and magnetism in (Sm0.58Y0.42)2
CuO4by X-ray diffraction and ac susceptibility measurements.
X-ray diffraction and refinement results which have shown that
the main phase in (Sm0.58Y0.42)2CuO4 is tetragonal(I 4/m m m)
space group,and lattice constants is a=b=3.89857(21) A，
c=11.9018(9) A,and the structure is independent with temperature
( during temperature range 80K~295K). The temperature
dependent magnetic susceptibility of (Sm0.58Y0.42)2CuO4,showed
anomalies at 255 K and 11 K,respectively,the peak of 255K which
are attributed to the antiferromagnetic ordering of the copper
spins,and which also have spin glass behavior .On the other
hand,the peak of 11 K ,which are attributed to the
antiferromagnetic ordering of the Sm3+ spins.