Effect of Thickness on Properties of MgB2 Thin Films
Superconducting MgB2 films have been fabricated on sapphire substrate by the method of hybrid physical-chemical vapor deposition (HPCVD). The film thickness ranges from 75 nm to 3 μm. The investigation on the physical properties, such as the transition temperature, TC, the transition width, T, and the critical current density, JC, has indicated that the optimum film thickness is about 1 μm. At this thickness, Tc(onset) = 40.3 K and 0Tc = 0.15 K. At T = 5 K without external field, JC has been estimated as 5.6×105 A/cm2according to the Bean model. The film quality begins to degrade as the thickness exceeds 1 μm. This work has demonstrated that HPCVD is a simple but effective technique for the application in the production of MgB2 wires.
Yafang Han et al.
C. G. Zhuang et al., "Effect of Thickness on Properties of MgB2 Thin Films", Materials Science Forum, Vols. 546-549, pp. 2047-2050, 2007