Thickness Dependence of Critical Current Density in Thick MgB₂ Films

Mina Hanna, Shufang Wang, Joan M. Redwing, X. X. Xi, Kamel Salama

Abstract — A study was performed to examine the J_c 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 300 nm and 10 µm. The values of J_c range from 1.2 x 107 A/cm² for 300 nm to 1.9 x 10⁵ A/cm² for 10 µm film thickness at 20 K and self-field. The study shows that critical current density (J_c ) in MgB₂ films decrease with increasing film thickness, similar to that observed in YBCO coated conductors. The results were interpreted.

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