Fabrication and Characteristics of Superconducting/ Magnetoresistive mixed sensors

• Main Authors: Zong-Yang Yan, 顏宗揚
• Other Authors: Li-Min Wang
• Format: Others
• Language: zh-TW
• Published: 2014
• Online Access: http://ndltd.ncl.edu.tw/handle/77158456753380844908

碩士 === 國立臺灣大學 === 物理研究所 === 102 === In the thesis, we have studied the superconducting / magnetoresistive mixed sensors, which structure is YBCO/CeO2/ LCMO. The LCMO layers are grown on STO substrates by using plused layser deposition (PLD). Then we define the pattern by photo lithography and ion-milling. CeO2 and YBCO films are grown by PLD. The CeO2 layer is to avoid short between superconducting and ferromagnetism layer. The crystalline orientation and surface morphology are characterized by X-ray diffraction and atomic force microscope (AFM). The electric and magnetic properties are also studied by using four-point probe and magnetic property measurement system. We design two different type of magnetoresistance device. One is based on LCMO thin films, the other is tunneling magnetoresistance (TMR) junctions with artificial step-edge grain boundaries by using ion-milling. The metal-insulator transition temperature of LCMO is 256 K and superconducting YBCO films reveal a high transition TC. By measuring the characteristics of the divice, we find the maximum TMRmax is 37 %, which is non-YBCO loops in 230 K.