Examination on High-Q NMR Transmit/Receiver Pickup Coils Made by YBa2Cu3O7-δ Thin Films
An important method to improve the sensitivity of a nuclear magnetic resonance (NMR) system is to increase the quality factor (<italic>Q</italic>) of the pickup coils. In this paper, we focus on the following three items: 1) effect of the surface resistance (<italic>R</italic><sub>s</sub>) of the YBa<sub>2</sub>Cu<sub>3</sub>O<sub>7-δ</sub> (YBCO) films on the <italic>Q</italic> of the NMR pickup coil; 2) relationship between coil line width and current flowing through coil; and 3) effect of Si-ion irradiation to YBCO films on the Q of the NMR pickup coils. In the study of 1), we examined the <italic>Q</italic> of the NMR pickup coils made by YBCO films with different <italic>R</italic><sub>s</sub> and found that reduction of <italic>R</italic><sub>s</sub> is useful in increasing the <italic>Q</italic> of the NMR pickup coils. In the study of 2), we simulated the current flowing in the NMR coils by an electromagnetic simulator, and found that wider microstrip lines of the NMR pickup coil increase the current. In the study of 3), we examined Si-ion irradiation effect to reduce <italic>R</italic><sub>s</sub> of YBCO films, and found low irradiation energy and low irradiation density of Si-ion is useful to decrease <italic>R</italic><sub>s</sub> and useful to obtain the high <italic>Q</italic> NMR pickup coils.