Experimental study in the development of HTS NMR probe

11th European Conference on Applied Superconductivity

Watanebe, M.^1 ; Sato, S.^1 ; Sato, K.^1 ; Ichikawa, K.^1 ; Saito, A.^1 ; Ohshima, S.^1

Graduate School of Science and Engineering, Yamagata University, 4-3-16 Jonan, Yonezawa, Japan^1

关键词: Artificial pinning centers;    Correlating equations;    Doping concentration;    Four-probe methods;    High DC magnetic fields;    Laser targets;    Microwave surface resistance;    YBCO thin film;   

Others  :  https://iopscience.iop.org/article/10.1088/1742-6596/507/1/012051/pdf
DOI  :  10.1088/1742-6596/507/1/012051

来源: IOP

【 摘 要 】

We investigated the effect of introducing artificial pinning centers (APCs) into YBa2Cu3O7-δ(YBCO) thin films to improve the critical current density (Jc) and reduce the microwave surface resistance (Rs) in a high dc magnetic field. Introduction of the APC was realized by dispersing BaHfO3(BHO) particulates in the YBCO thin films. Four types of sintered YBCO ceramics with x wt % (x 0.5, 1.0, 2.0) BHO were used as laser targets in order to fabricate YBCO thin films with various amounts of BHO and investigate the influence of the BHO doping concentration. Jcwas measured by a four probe method. We measured Jcin a magnetic field which was applied parallel to the c-axis (Jc(p)), and Jcin a magnetic field which was applied perpendicular to the c-axis (Jc(n)). The Rswas calculated using a correlating equation of Jcand Rs. The Jc(p) at 5 T and 20 K of 1.5 wt% BHO doped YBCO thin film was the largest at 3.4 MA/cm2. The Jc(n) of 1.5 wt% BHO doped YBCO thin film was 2.5 MA/cm2which is comparable to non-doped. The Rs(n) and Rs(p) of all YBCO thin films was less than 25 μΩ at 500 MHz. Therefore, we clarified the possibility that the most effective way to fabricate thin film for NMR coil application is by doping YBCO with BHO 1.5 wt%.