抄録
We fabricated large single-domain Sm-Ba-Cu-O bulk superconductors 60mm in diameter, which can trap magnetic fields exceeding 2 T at 77 K. We have proposed the construction of a superconducting bulk magnet (SBM) system by using the extremely powerful bulk superconductor cooled by a refrigerator. As one of promising applications, we have constructed a magnetron sputtering device by replacing a conventional Nd-Fe-B permanent magnet with an SBM. In our system, the magnetic field parallel to the target surface reached 0.6 T, which is more than ten times stronger than that of a conventional magnetron cathode. This strong magnet field enabled us to deposit films from various targets including a 3mm thick Fe at pressures lower than 1×(10)^<-2> Pa. To the best of our knowledge, the present magnetron sputtering is the only one which can be operated under such a low pressure range. For example, plasma damage-free films can be prepared by extending the target to substrate distance to 30-50cm, since the mean free path of sputtered particles becomes so long that they can reach the substrate without involving repeated collisions during their flight.
