Development of HTS Pickup Coils for 700-MHz NMR: Resonance Frequency Tuning Using a Sapphire Plate.

In this study, we developed a new frequency-tuning method for 700-MHz nuclear magnetic resonance (NMR) pickup coils. We determined an optimal Helmholtz-type one-turn coil, by using an electromagnetic simulator, and fabricated a pickup coil using \textYBa2\text{Cu}3\text{O}7-\delta (YBCO) thin films. We examined the resonance frequency shift of the pickup coils obtained with a sapphire plate by using a 3-D electromagnetic-field simulator and obtained a 31.5-MHz shift. We also examined the frequency shift obtained using a quasi-NMR pickup coil system and found that it was 29.3 MHz. This value is sufficient for the frequency tuning in an actual NMR system. It became clear that resonance frequency tuning using a sapphire plate was possible. [ABSTRACT FROM PUBLISHER]