Dependences of microwave surface resistance of HTS thin films on applied dc magnetic fields parallel and normal to the substrate

11th European Conference on Applied Superconductivity

Sato, K.^1 ; Sato, S.^1 ; Ichikawa, K.^1 ; Watanabe, M.^1 ; Honma, T.^1 ; Tanaka, Y.^1 ; Oikawa, S.^1 ; Saito, A.^1 ; Ohshima, S.^1

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

992-8510, Japan^1

关键词: Applied magnetic fields;    DC magnetic field;    Dielectric resonator method;    High temperature superconductor (HTS);    Magnetic field dependences;    Microwave surface resistance;    Temperature dependence;    Zero magnetic fields;   

Others  :  https://iopscience.iop.org/article/10.1088/1742-6596/507/1/012045/pdf
DOI  :  10.1088/1742-6596/507/1/012045

来源: IOP

【 摘 要 】

We investigated the dc magnetic field and temperature dependences of microwave surface resistance (Rs) of high-temperature superconductor (HTS) films. Previously, we reported that the surface resistance RsRs(n)under a dc magnetic field applied normaly to the substrate increased when increasing the applied magnetic field. For NMR application, we have to examine the Rs(p)under the dc magnetic field parallel to the substrate. We measured the Rs(p)of the YBCO and DyBCO thin films with a thickness of 500 nm deposited on a MgO (100) substrate using the dielectric resonator method at 21.8 GHz, and a dc magnetic field of up to 5 T. In a zero magnetic field, the values of Rs(n)and Rs(p)were 0.35 mQ at 20 K. Under the dc magnetic field, the Rs(n)and the Rs(p)also increased with increasing magnetic field, however, the Rs(p)had a lower magnetic field dependence and the value was about 1/10 of that of the Rs(n). The Rs(p)at 16.4 T and at 700 MHz could be estimated by the two-fluid model. The Rs(p)value was about 1/2600 compared with that of copper at 20 K. As a result, we clarified that 500 nm thick YBCO and DyBCO thin films could provide advantages for NMR application.