The Fabricate Of High Tc Superconductor Thin Filme And Application Of Its Devise In The Low Field NMR

Now,the high field nuclear magnetic respnance(NMR)is usually used in the medical or research.The high field is produced by the superconductor loops,so it costs much prices. Therefore,when the sample in the high field,it will broken some intrinsic characters of the sample.Contrast the disadvantages of the high field NMR,this article put a method that obtain the low field NMR signal by use the DC-Super Conductor QUantum Interference Device(SQUID).At first,we have fabricates YBCO thin film with higher quality.We measured the characteristic of it and show that the Tc is about 90K and the change width is less than 1K. When carrying through the experiment of X-ray diffraction,from the curve we can see the thin film with preferably tropism and basically no mixed phase appears.In the same way,we fabricated the high Tc DC-SQUID magnetometer on the bicrystal substrates.The measurement Of noise spectrum at 77K showed that the white noise at.200Hz is about 400fT/(?)Hz.At last,we design the system of DC SQUID ma(?)netometer detecting the NMR signal in the magnetically shield room.Used the water as our sample,at the polarization magnet field of 10mT and the measure field between 19.94μT to 7.64μT(correspond frequency from 823Hz to 323.6Hz),we observed the resonance spectrum come from the ~1H in the water.The half width of the spectrum is about 1Hz.The signal-noise ratio with one time measurement may reach 4,and we put the signal average time after time that can advance the signal-noise ratio.