Electrical and structural properties of MgB2 films prepared by sequential deposition of B and Mg on the NbN buffered Si(100) substrate

摘要

We introduce a simple method of an MgB2 film preparation using sequentialelectron-beam evaporation of B-Mg two-layer (followed by in-situ annealing) onthe NbN buffered Si(100) substrate. The Transmission Electron Microscopyanalyses confirm a growth of homogeneous nanogranular MgB2 films without thepresence of crystalline MgO. A sensitive measurement of temperature dependenceof microwave losses shows a presence of intergranular weak links close thesuperconducting transition only. The MgB2 films obtained, about 200 nm thick,exhibit a maximum zero resistance critical temperature of 36 K and criticalcurrent density of 3x10^7 A/cm^2 at 13.2 K