Ag-In-Mg-Yb準晶的電導率均隨溫度降低而升高，也就是它們的電阻比 均大於1，這是高品質的金屬態準晶常見現象，這種現象可用量子干涉效應來解釋。Ag-In-Yb準晶在低真空曝露太久(即老化(aging)的意思)，其低溫電阻會下降。我們發現這是樣品氧化的緣故。
利用掃描式電子顯微鏡觀察被氧化的表面，發覺氧化來自於Yb元素，而且Yb的氧化物會將In、Ag推擠到被氧化區域的邊緣。因此我們認為Yb的氧化會破壞準晶的結構，和引起含有Ag和In組成的金屬相或單獨的Ag及In金屬相析出，是導致低溫電阻的下降的原因。
我們發現利用感應爐所製成的Ag-In-Mg-Yb準晶樣品，其實際成分都比用電弧爐製成的樣品更接近配方的成分(nominal composition)，因此用前一方法所製成的樣品較方便用來研究準晶物性與成份的變化關係。

The electrical resistivity of the studied Ag-In-Mg-Yb quasicrystals all increases with the decrease of temperature. i.e., their resistivity ratios are all greater than one. The low-temperature resistivity of Ag-In-Mg-Yb QCs was found to reduce as the samples were aged in air at room temperature. In this work, we clearly show that this is attributed to the oxidation of sample surface. Using a SEM in a BSE mode to examine the sample surface, we found that the oxidation mainly results from Yb elements and In and/or Ag elements were possibly pushed to the edge of the oxidized areas as the Yb oxide was formed. Thus, we think the formation of Yb oxide starting on the sample surface could at the end destroy the quasicrystalline structure and cause the precipitate of Ag. Ag and/or In-containing metallic phase and therefore, lead to the reduction of the low-T resistivity. We also found that the Ag-In-Mg-Yb samples prepared by an induction furnace have the true composition close to the nominal composition than those prepared by an arc furnace. This makes it easier to study the composition dependence of the physical properties of quasicrystals.

參考資料
1. J. Q. Guo, E. Abe, and A. P. Tsai, Phys. Rev. B 62, R14605 (2000).

2. 黃嘉賢，“二元Cd-Yb準晶與類準晶的一些物理特性”，國立成功大學物理研究
所碩士 論文 (2003)。

3. 王永豪，“Ag-In-Yb準晶的製造與其電性的之研究”，國立成功大學物理研究
所碩士論文 (2004)。

4. 賴賢修，“Cd84.5-xMgxYb15.5和(AgIn)84.5-xMgxYb15.5準晶材料電傳輸性質
的研究
5. V. Elser, Phys. Rev. B 32, 4892 (1985).

6. J. Q. Guo, and A. P. Tsai, Philos. Mag. Lett. 82, 349 (2002)