本實驗利用電子束微影技術製作了鐵磁-超導-鐵磁單電子電晶 體，來研究其中的自旋相關傳輸現象。當鐵磁-超導-鐵磁單電子電晶 體兩邊接腳的磁化強度(magnetization)為反鐵磁排列時，穿隧電流會 使得中間超導體層的電子自旋組成不平衡，這不平衡的結果導致超 導性的破壞，而且超導性的破壞隨偏壓的增加而減少，隨溫度的增 加而減少，這些現象目前在理論上並沒有很好的解釋。 在應用上，這個實驗發現了一種利用小磁場即可以控制超導層 中超導性的方法，可以利用這個特點製作成磁電子方面的元件。 This experiment is to use E-beam lithography to fabricate Ferromagnet /Superconductor/ Ferro-magnet Single Electron transistor (SET) and to study the phenomena of spin-dependent transport. The tunneling current in the anti-ferromagnetic alignment of the magnetizations gives rise to spin imbalance in the superconducting island. The resulting nonequilibrium spin density strongly suppresses the superconductivity, and the effect is weakened with increasing bias voltage and with increasing temperature. The origin of the bias voltage and temperature dependences are not fully understood. In conclusion, we have found a new method to control superconductivity of a superconducting island by appling a small magnetic field, which provides a new mechanism for a superconducting spin electronic device.
