A study was performed to examine the Jc behavior as a function of thickness in MgB2 films fabricated by ex situ annealing at 840 °C of boron films, grown by chemical vapor deposition, in Mg vapor. The film thicknesses range between 300nm and 10νm. The values of Jc range from 1.2 × 107Acm-2 for 300nm to 1.9 × 10 5Acm-2 for 10νm film thicknesses at 20K and self-field. The study shows that the critical current density (Jc) in MgB 2 films decreases with increasing film thickness, similar to that observed in YBCO-coated conductors. Moreover, our study shows that critical current (Ic) reaches its maximum value of 728Acm-1 width at ∼1νm thick MgB2 films at 20K and self-field, which is, interestingly, the same thickness of pulsed-laser-deposited YBCO-coated conductors at which Ic reaches its maximum value. The high J c values carried by our films show that the ex situ fabrication method can produce high quality MgB2 films at low processing temperatures, which is promising for RF cavity applications and coated-conductor wires and tapes.
All Science Journal Classification (ASJC) codes
- Ceramics and Composites
- Condensed Matter Physics
- Metals and Alloys
- Materials Chemistry
- Electrical and Electronic Engineering